CA2558984A1

CA2558984A1 - Recombinant chondroitinase abc i and uses thereof

Info

Publication number: CA2558984A1
Application number: CA002558984A
Authority: CA
Inventors: Vikas Prabhakar; Ishan Capila; Rahul Raman; Carlos Bosques; Kevin Pojasek; Ram Sasisekharan
Original assignee: Massachusetts Institute Of Technology; Vikas Prabhakar; Ishan Capila; Rahul Raman; Carlos Bosques; Kevin Pojasek; Ram Sasisekharan
Current assignee: Massachusetts Institute of Technology
Priority date: 2004-03-10
Filing date: 2005-03-10
Publication date: 2005-09-22
Also published as: US20070148740A1; US20060078959A1; WO2005087920A3; US20070224670A1; US7592152B2; US7662604B2; US20070148157A1; WO2005087920A2; US7553950B2; US7507570B2; US20070202563A1; US8338119B2; EP1737954A2

Abstract

The invention relates to chondroitinase ABC I and uses thereof. In particular, the invention relates to recombinant and modified chondroitinase ABC I, their production and their uses. The chondroitinase ABC I enzymes of the invention are useful for a variety of purposes, including degrading and analyzing polysaccharides such as glycosaminoglycans (GAGs). These GAGs can include chondroitin sulfate, dermatan sulfate, unsulfated chondroitin and hyaluronan.
The chondroitinase ABC I enzymes can also be used in therapeutic methods such as promoting nerve regeneration, promoting stroke recovery, treating spinal cord injury, treating epithelial disease, treating infections and treating cancer.

Description

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JUMBO APPLICATIONS / PATENTS
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RECOMBINANT CHONDROITINASE ABC I AND USES THEREOF
GOVERNMENT SUPPORT
Aspects of the invention may have been made using funding from National Institutes of Health Grant number GM57073. Accordingly, the Government may have rights in the invention.
FIELD OF THE INVENTION
The invention relates to chondroitinase ABC I and uses thereof. In particular, the to invention relates to recombinantly produced and/or purred ch~ndroitinase ABC I as well as to modified versions of the enzyme. Also provided are methods of producing and uses for the enzymes, which include cleaving and analyzing polysaccharides, such as glycosaminoglycans, particularly galactosaminoglycans (GalA~rs). The invention further relates to polysaccharides that are produced as a result o~ their interaction with the enzymes provided. These polysaccharides or the enzymes provided, alone or in combination, can be used in methods of treatment, such as, promoting nerve regeneration, promoting stroke recovery, treating spinal cord injury, treating epithelial disease, treating infections and treating cancer.
2o BACKGROUND OF THE INVENTION
Glycosaminoglycans (GAGS) are linear, acidic polysaccharides that exist ubiquitously in nature as residents of the extracellular matrix (ACM) and at the cell surface, as constituents of proteoglycans, of many different organisms of divergent phylogeny (Habuchi, O. (2000) Biochina Bioplays Acta 1474, 11 S -27;
Sasisekharan, R., Bulmer, M., Moremen, K. W., Cooney, C. L., and Langer, R. (1993) Pr~oc Natl Acad Sci USA 90, 3660-4). Glycosaminoglycans consist of a disaccharide repeat unit of a hexosamine linked to an uronic acid. These sugars, apart from having important structural roles in the ECM, are also fundamental modulators of many biological processes like development, cell proliferation, signaling and inflammation (Bernfield, 3o M., Gotte, M., Park, P. W., Reizes, O., Fitzgerald, M. L., Lincecum, J. and Zako, M.
(1999) Functions of cell surface heparan sulfate proteoglycans. Annu Rev Biochem 68, 729-777; Sugahara, K., Mikami, T., Uyama, T., Mizuguchi, S., Nomura, I~. and

-2-Kitagawa, H. (2003) Recent advances in the structural biology of chondroitin sulfate and dermatan sulfate. Curr Opin Struct Biol 13, 612-620.) GAGS act as critical modulators of a number of biochemical signaling events (Tumova, S., Woods, A., and Couchman, J.
R. (2000) Int J Biochern Cell Biol 32, 269-88) requisite fox cell growth and differentiation, cell adhesion and migration, and tissue morphogenesis.
Chondroitin sulfate (CS)/dermatan sulfate (DS) polysaccharides have been implicated in a variety of biological phenomena ranging from anticoagulation to osteoarthritis (Mascellani, G., Liverani, L., Bianchini, P., Parma, B., Torn, G., Bisio, A., Guerrini, M., and Casu, B.
(1993) Bioclaern. J. 296, 639-48; Achur, R. N., Valiyaveettil, M., Alkhalil, A., to Ockenhouse, C. F., and Gowda, D. C. (2000) J. Biol. Chern. 275, 40344-S6;
and Plaas, A. H., West, L. A., Wong-Palms, S., and Nelson, F. R. (1998) J. Biol. Claena.
273, I2642-9). In addition, modification of existing GAG sequences by chondroitinase ABC
and chondroitinase AC may inhibit angiogenesis and tumor metastasis (Denholm, E.M.
et al.
(2001) Eur. J. Pharrnacol. 416, 213-21).
25 The chemical heterogeneity of GAGs is responsible for their wide-ranging biological influence. Each GAG disaccharide repeat unit can be customized through a variety of biosynthetic modifications that include epimerization of the uronic acid and variable sulfation. The specific sequence of chemical modifications on GAG
chains imparts a potential for interaction with other biological agents, including growth factors, 20 cytokines, and other signal transducers. Even more, specific sequences within the oligosaccharide chain have been shown to be activating, and others inhibitory, with regard to specific biological processes (Bao, X., Nishimura, S., Mikami, T., Yamada, S., Itoh, N. and Sugahara, K. (2004) Chondroitin sulfate/dermatan sulfate hybrid chains from embryonic pig brain, which contain a higher proportion of L-iduronic acid than 25 those from adult pig brain, exhibit neuritogenic and growth factor binding activities. J
Biol Chem 279, 9765-9776.) This emerging paradigm of structure-function glycobiology promises to create new strategies for the crafting of medical interventions.
The development of complementary biochemical tools that cleave GAGS in a sequence-specific fashion has enabled progress in the polysaccharide sequencing field.
3o Many microorganisms express GAG-degrading enzymes for the purpose of facile invasion of host tissue and to acquire nutrition from decaying animal tissues (Ernst, S.,

-3-Langer, R., Cooney, C. L. and Sasisekharan, R. (1995) Enzymatic degradation of glycosaminoglycans. Crit Rev Biochem Mol Biol 30, 387-444.) A number of these enzymes have been cloned and sequenced and are being developed in polysaccharide sequencing methodologies and other industrial applications. These include heparinases I, II, and III and chondroitinases AC and B (cAC and cB, respectively) from Flavobacteriurn heparinurn (Venkataraman, G., Shriven Z., Raman, R. and Sasisekharan, R. (1999) Sequencing complex polysaccharides. Science 286, 537-54;
Sasisekharan, R., Bulmer, M., Moremen, K. W., Cooney, C. L. and Langer, R.
(1993) Cloning and expression of heparinase I gene from Flavobacterium heparinum.
Proc Natl to Acad Sci U S A 90, 3660-3664; Godavarti, R., Davis, M., Venkataxaman, G., Cooney, C., Langer, R. and Sasisekharan, R. (1996) Heparinase III from Flavobacterium heparinum: cloning and recombinant expression in Escherichia coli. Biochem Biophys Res Commun 225, 751-758; Pojasek, I~., Shriver, Z., Kiley, P., Venkataraman, G. and Sasisekharan, R. (2001) Recombinant expxession, purification, and kinetic z5 characterization of chondroitinase AC and chondroitinase B from Flavobacterium heparinum. Biochem Biophys Res Commun 286, 343-351.) Overall, the role of GAGs as specific mediators of tumorigenesis and other biological events is an emerging field that offers the potential for the development of novel therapeutics (Shriver, Z. et al.
(2002) Trends. Cardiovasc. Med. 12, 71-7; and Liu, D. et al. (2002) P~°oc. Natl. Acad.
2o Sci. USA 99, 568-73).
SUMMARY OF THE INVENTION
The invention provided relates, in part, to chondroitinase ABC I (cABC I) enzymes and methods for their production and use. In one aspect of the invention a 25 cABC I enzyme that has the amino acid sequence of SEQ ID NO: 2 is provided.
In another aspect of the invention a polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or a fragment thereof is provided. The fragment, for example, can be any portion of the amino acid sequence of SEQ ID NO: 2 up to the full length of the sequence provided that the fragment is at least 8 amino acids in length. In some 3o embodiments the fragment is at least 10, 15, 20, 30, 50, 75, 125, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 950, 975, 990 or more amino acids in length.

_ q. _ The enzymes provided, in some aspects, include modified versions of native chondroitinase ABC I enzymes. Therefore, in one aspect, a modified chondroitinase ABC I is provided. In one embodiment the modified chondroitinase ABC I enzymes have the amino acid sequence of a native cABC I enzyme with amino acid substitutions of conserved residues, potential general bases, and/or residues in close proximity to potential general bases and which seem to protrude into the catalytic cleft.
The modified chondroitinase ABC I enzymes, in one embodiment, has the amino acid sequence of the peptide (mature or immature) of a native chondroitinase ABC I, wherein at least one residue, such as at position 105, 131, 154, 218, 219, 221, 222, 253, 276, 286, 309, 312, to 322, 388, 389, 392, 439, 442, 444, 490, 500, 501, 508, 560, 561, 587, 653, 678, 694 or 712, has been substituted with a different amino acid than in the native chondroitinase ABC I. The residue numbering provided herein is consistent with that found in the literature. Namely the numbering is based on the numbering of the immature sequence (with the signal peptide), such as, for example, the numbering of the native chondroitinase ABC I sequence given by GenBank Accession Number P59807. In one embodiment the amino acid sequence of the modified chondroitinase ABC I is not the amino acid sequence of any of SEQ ID NOs: 3-24.
The chondroitinase ABC I enzymes and polypeptides provided herein can in some embodiments include the signal sequence. In other embodiments they do not 2o include the signal sequence.
Modified chondroitinase ABC I enzymes can be produced using conservative substitutions, non-conservative substitutions, deletions or multiple mutant combinations of any of the residues provided herein. In some embodiments the modified chondroitinase ABC I enzymes are produced by substituting l, 2, 3, 4, 5, 6, 7, 8, 9, 10, z5 15, 20, 25, 30, 35, 40, 50 or more residues of a native chondroitinase ABC
I enzyme with a different amino acid than that found in the native enzyme. In some embodiments the nucleic acid molecule encoding the modified chondroitinase ABC I enzyme is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% homologous to the nucleic acid that encodes the native enzyme. The enzymes encoded by such nucleic 3o acids are also provided herein.

In one embodiment the modified chondroitinase ABC I is produced by substituting at least one of the residues described herein with an amino acid such as alanine, histidine, cysteine, phenylalanine, isoIeucine, Ieucine, methionine, lysine, proline, arginine, tyrosine, aspartic acid, glutamic acid, glutamine or serine provided that the substituting amino acid is different from the residue found in the native enzyme. In another embodiment the residue is substituted with alanine. In still another embodiment the residue is substituted with an amino acid residue that is not alanine. In one embodiment the residue substituted is the residue at position 501 and/or 508 and the residue is substituted with an amino acid other than alanine. In another embodiment the residue substituted is the residue at position 154 and the residue is substituted with an amino acid other than alanine.
In one embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 154 with alanine. In another embodiment the modified chondroitinase ABG I is produced by substituting the residue at position 221 with alanine, lysine; methionine or glutamine. In still another embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 309 with isoleucine. In still a further embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 322 with leucine. In yet another embodiment the modified chondroitiriase ABC I is produced by substituting the residue at position 388 2o with alanine, lysine or arginine. In still another embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 389 with alanine, lysine or arginine. In yet another embodiment the modified chondroitinase ABC I is produced by substituting the residua at position 392 with alanine or phenylalanine. In still a further embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 439 with alanine. In yet another embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 442, 444, and/or 490 with alanine. In still a further embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 493 with alanine. In still another embodiment the modified chondroitinase ABC I is one where the residue at position 500 is substituted with alanine, methionine, cysteine, glutamine or lysine. In still another embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 501 with alanine, lysine or arginine. In still another embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 508 with phenylalanine. In yet another embodiment the modified chondroitinase ABC I is one where the residue at position 564 is substituted with alanine, methionine, glutamine or lysine. In a further embodiment the modified chondroitinase ABC I is one where the residue at position 561 is substituted with alanine. In still a further embodiment the modified chondroitinase ABC I is produced by substituting the residue at position 653 with alanine, aspartic acid or glutamine. In another embodiment the residue at position 694 is substituted with proline or glutamine. In another embodiment the residue at position 712 is substituted with alanine.
In another aspect of the invention a modified chondroitinase ABC I which has the amino acid sequence of the peptide of a native chondroitinase ABC I, and the amino acid sequence contains at least one residue at position 105, 131, 154, 218, 219, 221, 222, 253, 276, 286, 309, 312, 322, 388, 389, 392, 439, 442, 444, 490, 500, 501, 508, 560, 561, 587, 653, 678, 694 or 712 of native chondroitinase ABC I and at Ieast one amino acid substitution is provided. The at least one amino acid substitution refers to one or more substitutions of one or more residues other than the residues or set of residues that are maintained from the native enzyme. The at least one amino acid subsitution can be a substitution of at least one of the residues recited above provided that the residues) is/are not of the set to be maintained in the enzyme. The at least one amino acid substitution can be a substitution of a residue that is not one of the residues recited above. The residue, in one embodiment, can be remote from the catalyic, substrate binding and/or calcium coordination motif sites of cABC I. In another embodiment the amino acid sequence of the modified chondroitinase ABC I is not the amino acid sequence of any of SEQ ID NOs: 3-24. In one embodiment the modified chondroitinase ABC I enzyme maintains at least the residue at position 501 of the native enzyme and further includes at least one amino acid substitution of some other residue.
In still another embodiment the modified chondroitinase ABC I enzyme maintains at least one of the residues at positions 501, 508, 560, or 653 or some combination thereof of the 3o native enzyme and further includes at least one amino acid substitution of some other residue than those maintained. The modified chondroitinase ABC I enzymes of this _7_ aspect of the invention can contain any of the residues provided herein or combinations thereof which are found in a native chondroitinase ABC I enzyme and at least one amino acid substitution. In one embodiment the modified chondroitinase ABC I has an amino acid sequence that contains the residues at positions 501, 508, 560 and 653 of a native chondroitinase ABC I and at least one amino acid substitution.
Modified chondroitinase ABC I enzymes that have altered Km or I~at values as compared to a native cABC I enzyme are also provided. In some embodiments the modified chondroitinase ABC I enzymes have a Km that is at least 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 11-, 12-, 13-, 14-, 15-, 16-, 17-, 18-, 19-, 20-, 25-, or 30-fold or more higher or lower than the Km of the native enzyme. In other embodiments the modified chondroitinase ABC I enzymes have a I~at that is at least 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 15-, 20-, 25-, 30-, 50-, 75-, 100-, 150-, 200-, 300-, 500-, 750-, 1000-, 1500-, 2000-, 3000-fold or more higher or lower than the I~at of the native enzyme.
Therefore, the modified chondroitinase ABC I enzymes provided herein can have increased or decreased activity when acting on a particular substrate. In one embodiment the modified enzymes has a lc~at or KM value for a substrate that is at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% different from a k~$t or KM value of a native enzyme. In another embodiment the modified chondroitinase ABC I has a lc~at or KM value for a substrate that is at least 10% different than a native chondroitinase ABC I
l~at or KM value. In yet another embodiment the modified chondroitinase ABC I
has a lc~at or KM value that is at least 20% different than a native chondroitinase ABC I k~at or KM value. In still another embodiment the modified chondroitinase ABC I has a lc~at or KM value that is at least 50% different than a native chondroitinase ABC I
lc~at or KM
value.
As provided above, the modified chondroitinase ABC I enzymes provided herein can have altered activity when compared to a native chondroitinase ABC I
enzyme. In one embodiment the modified chondroitinase ABC I enzymes produce a modified product profile that is different from the native product profile. In one embodiment the modified product profile is at least 5°/~, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% different from a product profile of a native cABC I enzyme. In one embodiment the modified product profile can be at least 10% different than a native product profile of a _g_ native chondroitinase ABC I. In another embodiment the modified product profile is at least 20% different than a native product profile of a native chondroitinase ABC I. In yet another embodiment the modified product profile is at least 50% different than a native cABC I product profile. In one embodiment the modified chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I and has a residue at position 508 that is substituted with phenylalanine. In another embodiment the modified chondroitinase ABC I has the amino acid sequence of a native chondroitinase ABC I and has a residue at position 560 that is substituted. In another embodiment the amino acid of the modified chondroitinase ABC I enzyme is not the amino acid sequence of any of l0 SEQ ID NOs: 3-24.
The substrates on which a native or modified cABC I enzyme provided herein can act include any polysaccharide. In one embodiment the polysaccharide is a glycosaminoglycan. Tn another embodiment the polysaccharide is a galactosaminoglycan. In still another embodiment the polysaccharide is chondroitin, chondroitin sulfate, dexTnatan sulfate, chondroitin 4-sulfate, chondroitin 6-sulfate, chondroitin D (CSD), chondroitin E (CSE), hyaluronan ox some combination thereof.
Provided herein are chondroitinase ABC I enzymes that selectively degrade a particular substrate and/or have altered substrate specificity. In one embodiment the substrate is chondxoifiin sulfate, and a modified chondroitinase ABC I that selectively 2o degrades chondroitin sulfate is provided. In one embodiment the modified chondroitinase ABC I has the amino acid sequence of a native chondroitinase ABC I and has a xesidue at position 388 or 389 or a combination thereof that is substituted with alanine, lysine or arginine. In another embodiment the modified chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I and has a residue at position 500 that is substituted with alanine. In still another embodiment the modified chondroitinase ABC I has the amino acid sequence of a native chondroitinase ABC I and has a residue at position 653 that is substituted with alanine, lysine or arginine.
In another embodiment a chondroitinase ABC T that selectively degrades dermatan sulfate is provided. In one embodiment the chondroitinase ABC I has the 3o amino acid sequence of a native chondxoitinase ABC I and has a residue at position 560 that is substituted with alanine or lysine.

In yet another embodiment a chondroitinase ABC I that selectively degrades chondroitin 6-sulfate is provided_ In one embodiment the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I and has a residue afi position S00 that is substituted with cysteine or lysine.
In still a further embodiment a chondroitinase ABC I that selectively degrades chondroitin 4-sulfate is provided_ In one embodiment the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I and has a xesidue at position 221 that is substituted with alanine. In another embodiment the chondroitinase ABC
I has the amino acid sequence of a native chondroitinase ABC I and a residue at position 500 that i0 is substituted with glutamine.
Also provided herein are chondroitinase ABC I enzymes that are DS-exclusive enzymes or CS-exclusive enzymes. In one embodiment the chondroitinase ABC I
enzyme is one where the residue at position 105, 312, and/or 388 has been substituted with a different amino acid than that found in a native cABC I enzyme. cABC I
enzymes with chondroitinase AC(cAC)-like activity include modified chondroitinase ABC I enzymes that have the amino acid sequence of a native chondroitinase ABC
I and a residue at position 388 and/or 389 that is substituted with alanine, lysine or arginine.
Another cABC I enzyme with cAC-like activity is a modified chondroitinase ABC
I that has the amino acid sequence of a native chondroitinase ABC I and a residue at position 500 that is substituted with alanine. cABC I enzymes with chondroitinase B(cB)-like activity are also provided. In one embodiment the chondroitinase ABC I with cB-like activity has the amino acid sequence of a native chondroitinase ABC I and has a residue at position 560 that is substituted with alanine or lysine. In other embodiments chondroitinase ABC I enzymes that are specific for hyaluronan-based GAGs are also provided. cABC I enzymes that have such specificity for certain GAGS
engineered out of the enzymes are also provided.
Chondroitinase ABC I enzymes with an altered calcium coordination motif are alaso provided. It has now been found that the residues at positions 442, 444 and 490 coordinate calcium ion and helps with the processing of substrates, such as dermatan 3o sulfate, by the enzyme. Therefore, these residues can be manipulated to control enzyme activity. In one embodiment the activity is the processing of iduronic acid-containing glycosaminoglycans. In another embodiment the activity is the processing of dermatan sulfate or heparin sulfate. In one embodiment, therefore, a modified chondroitinase ABC
T enzyme is provided where a residue at position 442, 444 and/or 490 or some combination thereof is substituted. In another embodiment the substitutions) is with alanine. In yet another embodiment a modified chondroitinase ABC I enzyme is provided where the residue at position 442, 444 and 490 are substituted. In another embodiment the residues are each substituted with alanine.
In still a further embodiment the modified chondroitinase ABC I enzyme is one where the residue at 218, 219, 222, 312, 561 or 712 or some combination thereof is to substituted with alanine. In another embodiment the modified chondroitinase ABC I
enzyme is one where the residue at 309 is substituted with valine. Modified chondroitinase ABC I enzymes are pxovided where one or more of the residues described herein are substituted.
In another aspect of the invention polypeptides comprising the amino acid sequence of the enzymes described herein or fragments thereof are provided.
Nucleic acids encoding such polypeptides are also provided. In one aspect of the invention nucleic acids that encode the chondroitinase ABC I enzymes or polypeptides described herein are provided. In one embodiment the nucleic acid is the nucleic acid as provided by SEQ ID NO: 1. Tn another embodiment the nucleic acid is a degenerate or complement of the nucleic acid sequence of SEQ ID NO: 1. Also provided herein, therefore, are vectors containing the nucleic acids described as are methods of producing chondroitinase ABC I enzymes using such vectors. Therefore, in another embodiment the chondroitinase ABC I enzymes provided are in recombinant form, and preferably, in a substantially purified recombinant form.
In another aspect of the invention compositions comprising the chondroitinase ABC I enzymes, polypeptides, nucleic acids, etc. described herein are provided. In one embodiment the compositions further comprise a pharmaceutically acceptable carrier. In another embodiment the compositions provided further comprise a physiologically acceptable earner.
In one aspect of the invention a composition is provided that comprises a chondroitinase and a divalent ion. 'fhe ion can be any ion including, but not limited, to calcium ion, manganese ion, copper ion, iron ion, barium ion, magnesium ion, zinc ion and lanthanides. In one embodiment the ion is not zinc ion. In another embodiment the ion is a lanthanide, such as, terbium or lutetium. In yet another embodiment the calcium ion is in the form of CaCl2. The CaCl2 can be at any concentration. In some embodiments, the CaCl2 is at a concentration of at least l, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mM
or more in a composition. In one embodiment the CaCl2 is at a concentration of at least 5 mM. In another embodiment the CaCl2 is at a concentration of at least 10 mM.
In still another embodiment the CaCl2 is at a concentration of 10 mM. In other embodiments the chondroitinase can be chondroitinase B, chondropitinase AC, chondroitinase ABC I or to chondroitinase ABC II. Also provided in another aspect of the invention are compositions that include the chondroitinase enzyme, divalent ion and a pharmaceutically or physiologically acceptable carrier.
Compositions of a galactoaminoglycan-degrading enzyme and an enzyme stabilizer are also provided. In one embodiment the enzyme stabilizer is a protease inhibitor. Protease inhibitors include, but are not limited to, AEBSF, bestatin, E64 protease inhibitor, pepstatin A or phosphoramidon. In another embodiment the enzyme stabilizer is a water mimic, such as, for example, glycerol or dextran. In one embodiment the galactosaminoglycan-degrading enzyme is chondroitinase AC, chondroitinase B, chondroitinase ABC I, chondroitinase ABC II, chondro-4-sulfatase, 2o chondroi-6-sulfatase or hyaluronidase or some combination thereof. In another aspect of the invention compositions that include a galactosaminoglycan-degrading enzyme, an enzyme stabilizer and a pharmaceutically or physiologically acceptable carrier are also provided.
The compositions and enzymes provided herein can be used for a variety of purposes. In one aspect a method of degrading a polysaccharide, such as a glycosaminoglycan, by contacting the glycosaminaglycan with any of the enzymes or compositions provided herein in an amount effective to degrade the glycosaminoglycan is provided. In one embodiment the method can further include contacting the glycosaminoglycan with at least one other polysaccharide-degrading enzyme, such as a glycosaminoglycan-degrading enzyme or galactosaminoglycan-degrading enzyme.
Other glycosaminoglycan-degrading enzymes include heparinases, glycuronidases, sulfatases, etc. In one embodiment the methods for degrading a polysaccharide can be carried out in the presence of a divalent ion. Ions (e.g., zinc) can be inhibitory to enzyme function. Therefore, in one embodiment, methods and compositions are provided where zinc is not included. In another embodiment calcium is present while other ions, such as zinc, are not. In another embodiment the methods can further include the step of contacting the glycosaminoglycan and/or the glycosaminoglycan-degrading enzyme, such as a chondroitinase, with zinc ion. The introduction of zinc ion can inhibit the degradation reaction and can serve as a way to control the enzymatic reaction.
In some instances the presence of zinc may be desired to control the reaction of substrate and enzyne. Therefore methods of degrading polysaccharides are provided whereby two or more divalent ions can be introduced to the enzymatic reaction at the same or at different points of the reaction process. In one embodiment one of the ions is zinc ion.
In another embodiment the zinc ion is introduced after the introduction of another divalent ion to the reaction. The divalent ions can include any such ions known in the art including those described herein.
As another way to control polysaccharide degradation reactions, chelators may be used. Therefore, in one embodiment the methods provided can further include the step of introducing a chelator to the enzymatic reaction. In one embodiment the chelator is EDTA or EGTA.
2o Methods and compositions are also provided herein where a polysaccharide, such as, for example, dermatan sulfate, is processed in the presence of calcium. A
novel calcium-coordination site in proximity to the enzyme active site has been found. The residues at positions 490, 442, and 444 are important components of this calcium-coordination site. Modulating this site, as well as regulating calcium levels in reaction, are important parts of controlling activity. Therefore compositions and methods are provided whereby the presence of calcium is controlled. In one embodiment of such compositions and methods alterations of one or more of the calcium coordination motif residues of a cABC I enzyme can also be included.
In another aspect of the invention methods of degrading a polysaccharide, such as 3o a glycosarninoglycan, that include the step of contacting a polysaccharide, such as a glycosaminoglycan, with a polysaccharide-degrading enzyme, such as a galactosaminoglycan-degrading enzyme in the presence of an enzyme stabilizer.
In one embodiment the enzyme stabilizer is a protease inhibitor, such as A.EBSF, bestatin, E64 protease inhibitor, pepstatin A or phosphoramidon. In another embodiment the enzyme stabilizer is a water mimic, such as glycerol or dextran.
s cABC I enzymes have been analyzed in a variety of reaction conditions.
Enzyme-substrate reaction parameters can be chosen to control substrate specificity, the mechanism of action, and/or the product profile. These reaction parameters include salt (e.g., NaCI, NaAC), temperature, pH, buffer (Tris buffer, or phosphate buffer), and reaction volume. Therefore compositions and methods are provided whereby these reaction parameters or some combination thereof are controlled. In one aspect methods of degrading a polysaccharide are provided whereby the pH is controlled. In one embodiment a polysaccharide, such as a glycosaminoglycan, is contacted with a degrading enzyme in a solution with a pH greater than 7 but less than 8. In another embodiment the pH of the solution is altered after the polysaccharide is contacted with the degrading enzyme. In another embodiment the pH for acting on the polysaccharide is less than 9Ø In another embodiment the pH is 8Ø In still another embodiment the pH is 7Ø In yet another embodiment the pH is between 6.0 and 9Ø Tn still a further embodiment the pH is between 7.0 and 8Ø In one embodiment when a phosphate buffer is used and the substrate on which the enzyme acts is chondroitin sulfate, the pH is 7Ø
2o In another embodiment of the invention methods are provided whereby the buffer is controlled. In some embodiments the buffer is Tris buffer or phosphate buffer.
In another embodiment the ionic strength (salt concentration) is controlled.
In one embodiment the salt concentration is less than 500 rnM. In another embodiment the salt concentration is less than 400 mM. In still another embodiment the salt concentration is less than 250 mM. In one embodiment the salt concentration is between 50-500 mM. In still another embodiment the salt concentration is greater than 50 mM.
In yet another embodiment the salt concentration is between 60-125 mM. In still another embodiment the salt concentration is between 125-150 mM. In another embodiment the salt concentration is between 50-400, 150-400 or I50-500 rnM. In yet another 3o embodiment the salt concentration is between 50-125 mM. In still another embodiment the salt concentration when the substrate is chondroitin sulfate is 62.5 mM.
In a further embodiment the salt concentration is between 100-500 mM. In still another embodiment the salt concentration is between 100-250 mM. In one embodiment the salt concentration is 100, 125 or 250 mM. The salt can be any of those laiown in the art and include sodium chloride, sodium acetate, sodium sulfate or ammonium sulfate_ In one embodiment of the invention a method is provided whereby dermatan sulfate is contacted with an enzyme provided herein in the presence of salt.
In another embodiment of the invention methods are provided whereby the concentration of sodium acetate is controlled. In one embodiment sodium acetate is present at 25-150 mM. In another embodiment 50-100 mM sodium acetate is present. In IO yet another embodiment the sodium acetate is present at a concentration of 50 mM. In another embodimen the sodium acetate is present at a concentration of 100 mM.
In another aspect where chondroitin sulfate is the substrate, sodium acetate is included in the composition or method.
In yet another embodiment of the invention the temperature is controIIecT. In one embodiment the temperature is less than 40°C. In another embodiment the temperature is between 25-45°C. Tn still another embodiment the temperature is between 30-40°C. In yet another embodiment the temperature is between 25-40°C. In still another embodiment ~tlze temperature is between 30-37°C. In another embodiment the temperature is between 38-45°C or 38-50°C. In a further embodiment the temperature is 2o 40°C. In still another embodiment the temperature is 37°C.
In other aspects of the invention methods and compositions are provided whereby more than one of the reaction parameters are controlled.
In another aspect of the invention the degraded glycosaminoglycans produced by the methods described herein are also provided. Also provided are compositions that include the degraded glycosaminoglycans and a pharmaceutically or physiologically acceptable carrier.
In another aspect of the invention methods for selectively degrading a polysaccharide are also provided. In one aspect a method of selectively degrading chondroitin sulfate is given. In another aspect the method is a method of selectively 3o degrading dermatan sulfate. In another aspect the method is a method of selectively degrading chondroitin 6-sulfate. In still a further aspect the method is a method of selectively degrading chondroitin 4-sulfate.
In another aspect of the invention a method of analyzing a sample of polysaccharides by contacting the sample with any of the enzymes or compositions described herein is provided. Tn one embodiment the polysaccharides are glycosaminoglycans. In another embodiment the glycosaminoglycans are galactosaminoglycans. In one aspect of the invention the method of analysis is a method for sequencing. In another aspect the method is a method for identifying the presence of a particular polysaccharide in a sample. In still a further aspect of the invention the 1o method is a method for determining the purity of a sample of polysaccharides. In yet another aspect of the invention the method is a method for determining the composition of a sample of polysaccharides.
The enzymes and compositions provided can further be used in various treatrr~ent methods. For instance, in one aspect of the invention a method for promoting nerve regeneration is provided. In one embodiment the nexve regeneration is axon regeneration. In one embodiment the method is directed to the treatment of a subject that has had a central nervous system injury. In another embodiment the subject has had a spinal cord injuxy. In another embodiment the subject has a neurodegenerative disorder.
In yet a further embodiment the subject has had a stroke.
In another aspect of the invention the enzymes and compositions provided can be used in methods for treating cancer. In still another aspect of the invention methods for inhibiting angiogenesis are provided. In yet another aspect of the invention methods fox inhibiting coagulation are pxovided. In still another aspect of the invention methods fox treating psoriasis are provided. Tn yet another aspect of the invention methods fox treating osteoarthritis are provided. In still another aspect methods fox treating a microbial infection, such as maternal malarial infection, are provided. In yet anothex aspect of the invention methods for treating epithelial disease (e.g., cystic fibrosis) are provided. In still another aspect of the invention methods for treating viral, bacterial or pathogenic infection or provided. In these aspects the methods for treatment include 3o administering to a subject in need thereof an effective amount of a pharmaceutical preparation of the enzymes or compositions provided herein or a polysaccharide or group of polysaccharides that result from contact with the enzymes provided alone or in combination with other polysaccharide-degrading enzymes or both.
In another aspect pharmaceutical preparations are pa~rovided. The pharmaceutical preparation in one aspect includes the chondroitinase AB C I enzymes provided and a pharmaceutically acceptable carrier. In another aspect tl~e pharmaceutical preparation includes a degraded polysaccharide, such as a glycosaminoglycan, and a pharmaceutically acceptable carrier. In some aspects the pharmaceutical preparations include both the enzyme and the degraded glycosaminoglycan. In preferred embodiments the pharmaceutical preparations include sterile formulations of the enzymes or degraded polysaccharides or both. Sterilec~ formulations of any of the compositions described are also provided herein.
In another aspect of the invention a method for recombinantly expressing a chondroitinase ABC I polypeptide is provided. In still another aspect of the invention a method for preparing purified chondroitinase ABC I is also provided. In still other another aspect a method for recombinantly expressing and preparing a purified chondroitinase ABC I is provided. In one aspect of the inv ention a method for producing chondroitinase ABC I is provided which includes the steps of harvesting cells that express chondroitinase ABC I, Iysing the cells, obtaining supernatant, and in some way purifying or altering the supernatant (e.g., applying the supernatant to a column and eluting the chondroitinase ABC I from the column). In ore embodiment the method also includes putting the cells, supernatant, filtered supernatant or eluate on ice as part of one or more of the steps. The method also can include putting the cells, supernatant, filtered supernatant or eluate on ice between any of the steps (e.g., between 2, 3, 4 or more steps). In one embodiment the cells, supernatant, filtered supernatant or eluate are put on ice at least twice during the method for the production of chondroitinase ABC
I. The methods provided can also be used for the production/purification of other polysaccharide-degrading enzymes, such as glycosam~noglycan-degrading enzymes, galactosaminoglycan-degrading enzymes, chondroitinases, etc. In another aspect of the invention a method for producing chondroitinase ABC I is provided which includes the 3o steps of harvesting cells that express chondxoitinase ABC I, lysing the cells, obtaining supernatant, and in some way purifying or altering the supernatant (e.g., applying the _I7-supernatant to a column and eluting the chondroitinase ABC I from the column), wherein one or more of the steps include the use of one or more protease inhibitors.
In one embodiment the methods can also include filtering the supernatant, or purifying the enzyme with a Ni+2 column. The methods can further include the use of 6x-His tags that can be cleaved off. The 6x-His tags bind Ni+2 column and allows enzyme puxification from crude extract (e.g., as one chromatography step). In still another embodiment the methods include centrifugation to obtain a cell pellet. In one embodiment the pellet is not stored prior to further processing.
In another aspect of the invention the methods of production/purification are to performed rapidly. In one embodiment the methods are performed in about 4 hours or less. In another embodiment the methods are performed in about 5 hours or Less.
In still another aspect methods for producing the enzyme where the signal sequence is removed are provided.
In another aspect of the invention the chondroitinase ABC I or modified forms thereof are in a substantially purified recombinant form.
In one aspect of the invention a chondroitinase ABC I with a specific activity of mU/p,g or more is provided. In one embodiment the specific activity is at least 30, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200 rnU/~g or more. In still another embodiment the specific activity is at least 164 rnU/pg. In another embodiment the specific activity is 2o at least 197.9 or 230.6 mU/~,g. In another aspect of the invention a chondroitinase ABC
I enzyme is provided that has a specific activity that is 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 15 20-, 30, 40-, 50-fold or more greater than the activity of the enzyme obtained from a crude Iysate.
In a further aspect of the invention an immobilized chondroitinase ABC I which includes at Least one of the chondroitinase ABC I enzymes provided herein and a solid support membrane, wherein the chondroitinase ABC I is immobilized on the solid support membrane, is provided .
Also provided herein are drug delivery strategies of cABC I and its modified counterparts. These include fusion proteins, where the cABC I enzyme is conjugated to a targeting molecule, such as a cancer antigen, pathogen toxin or portion thereof, or a molecule that targets the glial scar. Therefore, the cABC I enzymes delivered with the _I8_ aid of a targeting molecule that has facile and specific localization to a physiological targets) can be used in the methods of treatment provided.
The compositions and methods provided can further include the use of other glycosaminoglycan-degrading enzymes, such as galactosaminoglycan-degrading enzymes. In some embodiments, such enzymes can include chondroitinase AC, chondroitinase B, chondroitinase ABC II, hyaluxonidase, chondro-4-sulfatase, chondro-6-sulfatase, mutant versions, functional equivalents or some combination thereof Each of the limitations of the invention can encompass various embodiments of the invention. It is, thexefore, anticipated that each of the limitations of the invention zo involving any one element or combinations of elements can be included in each aspect of the invention.
These and other aspects of the invention will be described in further detail in connection with the detailed description of the invention.
zs BRIEF DESCRIPTION OF THE FIGURES
Fig. 1 provides the results from the SDS-PAGE analysis of the purification of recombinant chondroitinase ABC I. The figure shows a summary of protein expression and purification following expression in BL21 (DE3) as 6x N-terminal fusion proteins.
Lanes: 1, cell pellet; 2, crude lysate; 3, Invitrogen SeeBIue Plus2 Pre-Stained Standard;
20 4, inactive recombinant chondroitinase ABC I; 5, active recombinant chondroitinase ABC I (altered via site-directed mutagenesis).
Fig. 2 illustrates the effect of varying chondroitinase ABC I biochemical reaction conditions. (A) pH profile; Inset (A) effect of buffer system on enzyme activity: (1) 50 mM Tris buffer pH 8.0; (2) 50 mM sodium phosphate buffer pH 8.0; white bars indicate 25 dermatan sulfate; black bars indicate chondroitin-6-sulfate; (B) effect of reaction temperature; (C) NaCI titration; (D) sodium acetate titration. Open white circles indicate dermatan sulfate; filled black circles indicate chondroitin-6-sulfate.
Fig. 3 provides the results of the kinetic analysis of chondroitinase ABC I on GaIAG substrates. The figure depicts the Hanes representations of recombinant 3o chondroitinase ABC I on chondroitin-4-sulfate (~), chondroitin-6-sulfate (o), and dermatan sulfate ( ~ j Fig. 4 depicts the results of the capillary electrophoretic analysis of recombinant active chondroitinase ABC I. The figure provides the product profiles for chondroitinase ABC I acting on (A) chondroitin-4-sulfate; (B) chondroitin-6-sulfate; and (C) dermatan sulfate (4Di4S = QUA-GalNAc4S, ~Di6S = QUA-GalNAc6S, 4Di2S6S = DUA2S-GalNAc6S, ADi4S6S = DUA-GalNAc4S6S). Impurities in commercial substrate preparations result in the 4Di6S peak in electrophoretogram (A) and the ~Di4S
peak in electrophoretogram (B).
Fig. 5 provides representative capillary electrophoresis profiles of chondroitinase ABC I mutants. The products of chondroitin-6-sulfate degradation following digestion by (A) His501A1a and (B) His561A1a are shown. Tables 4 and 5 provide further information regarding the substrate specificity of recombinant chondroitinase ABC I and its mutants.
Fig. 6 provides the circular dichroism spectra of chondroitinase ABC I and the inactive mutants. The recombinant chondroitinase ABC I (-) and the mutants His501A1a (""), Tyr508A1a (- - -), G1u663A1a (-w- ), and Arg560A1a (- ) were concentrated and buffer-exchanged into 50 mM sodium phosphate buffer, pH 8Ø
Proteins were analyzed in a quartz cell with a 1-mm path length. All spectra were collected using a protein concentration of 0.2 mg/ml in sodium phosphate pH
7Ø For melting experiments (inset), spectra were collected in 5°C intervals from 5°C to 80°C.
The slight deviations in spectra intensity can be attributed to errors inherent in protein quantification.
Fig. 7 depicts the comparison of three amino acid sequences of chondroitinase ABC I protein. The sequences of Sato et al. (SEQ ID NO: 4) and Khandke/Ryan (SEQ
ID NO: 3) et al. [13 and 14, Example 1J were compared to the sequence from the original truncated clone described in the Examples below.
Fig. 8 provides GaIAG disaccharide chemical structures. GAGS are polymers of repeated disaccharide units consisting of an uronic acid and a hexosamine. In the case of GaIAGs, the hexosamine moiety is a galactosamine.
Fig. 9 provides the circular dichroism spectra of recombinant enzymes. The recombinant cABC I (----) and the mutants His501Lys (w~), His501Arg (-- -- --) and G1u653Asp (-- . . --) were concentrated and buffer-exchanged into 50 mM sodium phosphate buffer, pH 8Ø The proteins were analyzed in a 1-mm path length quarhz cell.
The slight deviations in spectra intensity can be attributed to errors inherent in protein quantification.
Fig. 10 shows the results from the capillary electrophoretic analysis of chondxoitinase ABC T TyrS08 mutants. Product profiles for (A) Tyr508A1a acting on chondroitin-6-sulfate, (B) Tyr508Phe acting on chondroitin-6-sulfate, (C) Tyr508A1a acting on dermatan sulfate and (D) TyrS08Phe acting on dermatan sulfate are provided.
Depicted are the relevant amino acids, which illustrate the nature of the chemical groups involved and the relative protrusion of each sidechain into the catalytic pocket.
1o Fig. 11 provides the results from the capillary electrophoretic analysis of chondroitinase~ ABC I G1u653 mutants. The products of dermatan sulfate degradation following digestion by (A) G1u653A1a, (B) G1u653Asp and (C) G1u653G1n are shown.
Also depicted are the relevant amino acids. For each sidechain, the relative length of protrusion into the catalytic pocket and the potential to participate in hydrogen bonding z s deterniine end-product profiles.
Fig. 12 provides the structural comparison of chondroitinases AC and ABC I.
Grasp rendering of cAC (left) and cABC I (right) structural complexes with dermatan sulfate are shown. Note that the active site groove of cAC is more closed compared to that of cABC I. This narrower groove and the presence of TrpI27 and Trp42,7 in cAC
20 locks the dermatan substrate in an orientation that allows binding to the active site but does not allow cleavage. On the other hand, the wider active site of cABC I
provides room for the dexmatan substrate to re-orient during catalysis.
Fig. 13 depicts chondroitinase ABC I and the chondroitin-4-sulfate substrate.
Shown is a stereoview of C4S subsixate in the active site. The saccharide is shown as are 25 the basic amino acids (His, Axg and Lys), acidic amino acids (Asp and Glu) and Phe.
Shown is a detailed schematic of the different amino acids in the active site numbered according to the crystal structure and their proximity to the oligosaccharide.
Fig. 14 depicts chondroitinase ABC I and the dermatan sulfate substrate. Shown is a stereoview of DS in the active site. Shown is a detailed schematic of the interaction 3o between various active site amino acids and the dermatan substrate oriented optimally for proton abstraction (left) and proton donation (right). Note that the two schematics are -zl -shown for clarity. It is possible that there is a re-orientation of the substrate during catalysis.
Fig. 1S pxovides an illustration of the structure of cABC I as well as the results from the provides the results from the purification of recombinant chondroitinase ABC I.
Fig. I6 provides the results from the analysis of the kinetics of recombinant cABC I on two substrates, C6S and DS.
Fig. 17 provides the product profiles for the action of cABC I on two substrates, C6S and DS.
Fig. 18 provides the results of the structural characterization of recombinant io cABC I. Shown are the circular dichroism spectra as well as the Tm determination.
Fig. 19 shows the structures of chondroitin AC Iyase II and cABC I.
Fig. 20 shows the results from the biochemical characterization of the pxoposed active site. HSOlA, E653A, Y508A and R560A snowed no activity towards C6S and DS. The product profile of HSOlA on DS is also shown.
Fig. 21 shows the product profiles of tyrosine 508 mutants acting on C6S and DS.
Fig. 22 shows the activity of various G1u653 mutants acting on the substrates C6S and DS.
Fig. 23 provides the product profiles from the action of G1u653 mutants.
2o Fig. 24 provides the results from the kinetic analysis of a Tyr508 mutant as compared to cABC I against two substrates, C6S and DS.
Fig. 25 provides the results from the kinetic analysis of a G1u653 mutant ate.
compared to cABC I against two substrates, C6S and DS.
Fig. 26 provides a schematic depicting the calcium coordination motif.
Fig. 27 provides the results of the calcium titration experiment.
DETAILED DESCRIPTION
Members of the glycosaminoglycan (GAG) family of complex polysaccharides includes dermatan sulfate (DS), chondroitin sulfate (CS), heparin/heparan sulfate 3o (HSGAG), keratan sulfate, and hyaluronic acid. Chondroitin sulfate and dermatan sulfate glycosaminoglycan polysaccharides, have been implicated in biological processes ranging from osteoarthritis to anticoagulation. Dermatan sulfate is emerging as an important regulator of cellular signaling processes. An over-sulfated hexasaccharide found in DS
that binds heparin cofactor II and promotes a 1000-fold increase in anticoagulation is the most characterized biological paradigm for DS (Maimone, M. M., and Tollefsen, D. M.
(1991) J Biol Chem 266, 14830; Mascellani, G., Liverani, L., Bianchini, P., Parma, B., Torn, G., Bisio, A., Guernni, M., and Casu, B. (1993) Biochem J 296, 639-48).
Several recent studies have implicated DS in promoting FGF-7 mitogenic activity (Trowbridge, J.
M., Rudisill, J. A., Ron, D., and Gallo, R. L. (2002) J Biol Chem 277, 42815-20) and enhancing the activity of hepatocyte growth factor/scatter factor (Lyon, M., Deakin, J. A., to Rahmoune, H., Fernig, D. G., Nakamura, T., and Gallagher, J. T. (1998) J
Biol Chem 273, 271-8; Lyon, M., Deakin, J. A., and Gallagher, J. T. (2002) J Biol Chem 277, 1040-6), suggesting an important role for DS in mediating cell signaling.
Dermatan sulfate is just one member of a subset of the glycosaminoglycan (GAG) family of chemically heterogeneous polysaccharides that are involved in a wide range of biological processes. This subset is referred to as galactosaminoglycans (GalAGs). GalAGs are one of four classes of GAGs (Ernst, S., Langer, R., Cooney, C.
L. and Sasisekharan, R. (1995) Enzymatic degradation of glycosaminoglycans.
Crit Rev Biochem Mol Biol 30, 387-444.) Galactosaminoglycans are composed of a disaccharide repeat unit of uronic acid [a-L-iduronic (IdoA) or (3-D-glucuronic (GlcA)j (1-j3) linked to N acetyl-D-galactosamine (GalNAc). These basic disaccharide units (Fig. 8) are linearly associated via [i(1-~4) linkages to form polymers of chondroitin sulfate (CS) or dermatan sulfate (DS). The uronic acids of CS are exclusively GlcA; with DS, epimerization at the C-5 position of the uronic acid moiety during biosynthesis results in a mixture of IdoA and GlcA epimers. Chondroitin sulfate can be O-sulfated at the C-4 of the galactosamine (chondroitin-4-sulfate, C4S or CSA) or the C6 of the galactosamine (chondroitin-6-sulfate, C6S or CSC). For DS, C-4 sulfation of the galactosamine is a common modification and O-sulfation at C-2 of the IdoA moiety may also occur.
Other rare modifications in CS, such as 2-O or 3-O sulfation of the GlcA moiety, have also been reported (Nadanaka, S. and Sugahara, I~. (1997) The unusual tetrasaccharide 3o sequence GlcA beta 1-3GalNAc(4-sulfate)beta 1-4GlcA(2-sulfate)beta 1-3GalNAc(6-sulfate) found in the hexasaccharides prepared by testicular hyaluronidase digestion of shark cartilage chondroitin sulfate D. Glycobiology 7, 253-263; Sugahara, I~., Tanaka, Y., Yamada, S., Seno, N., I~itagawa, H., Haslam, S. M., Morris, H. R. and Dell, A.
(1996) Novel sulfated oligosaccharides containing 3-O-sulfated glucuronic acid from king crab cartilage chondroitin sulfate K. Unexpected degradation by chondroitinase ABC. J Biol Chem 271, 26745-26754.) GaIAGs include chondroitin and dermatan sulfate GAGS, such as C4S, C6S, DS, chondroitin, chondroitin D, chondroitin E
and hyaluronan. These complex biomacromolecules axe believed to be responsible for the inhibition of nerve regeneration following injury to the central nervous system. The enzymatic degradation of GAG chains in damaged nervous tissue by chondroitinase IO ABC I (cABC I), a broad specificity Iyase that degrades GalAGs, promotes neural recovery.
Several studies have implicated GaIAGs as key modulators of fundamental biological processes. Galactosaminoglycans interact with a wide variety of proteins such as growth factors, chemokines, lipoproteins and enzymes in the extracellular environment. These interactions play critical roles in modulating the function of the protein (Trowbridge, J. M. and Gallo, R. L. (2002) Dermatan sulfate: new functions from an old glycosaminoglycan. Glycobiology 12, 1178-1258; Sugahara, K., Mikami, T., Uyama, T., Mizuguchi, S., Nomura, K. and Kitagawa, H. (2003) Recent advances in the structural biology of chondroitin sulfate and dermatan sulfate. Cunr Opin Struct Biol 13, 612-620.) Dermatan sulfate is known to bind with thrombin (Liaw, P. C., Austin, R. C., Fredenburgh, J. C., Stafford, A. R. and Weitz, J. I. (1999) Comparison of heparin- and dermatan sulfate-mediated catalysis of thrombin inactivation by heparin cofactor II. J
Biol Chem 274, 27597-27604) and activated protein C (Fernandez, J. A., Petaja, J. and Griffin, J. H. (1999) Dermatan sulfate and LMW heparin enhance the anticoagulant action of activated protein C. Thromb Haemost 82, 1462-1468) to influence anticoagulation; collagen (Iozzo, R. V. (1997) The family of the small leucine-rich proteoglycans: key regulators of matrix assembly and cellular growth. Crit Rev Biochem Mol Biol 32, 141-174), fibronectin (Tumova, S., Woods, A. and Couchman, J. R.
(2000) Heparan sulfate chains from glypican and syndecans bind the Hep II domain of 3o fibronectin similarly despite minor structural differences. J Biol Chem 275, 9410-9417;
Schmidt, G., Robenek, H., Harrach, B., Glossl, J., Nolte, V., Hormann, H., Richter, H.

and I~resse, H. (1987) Interaction of small dermatan sulfate proteoglycan from fibroblasts with fibronectin. J Cell Biol I04, 1683-I69I; Walker, A. and Gallagher, J. T.
(1996) Structural domains of heparan sulphate for specific recognition of the C-terminal heparin-binding domain of human plasma fibronectin (HEPII). Biochem J 317 ( Pt 3), 87I-877), and tenascin-X (Elefteriou, F., Exposito, J. Y., Garrone, R. and Lethias, C.
(2001) Binding of tenascin-X to decorin. FEBS Lett 495, 44-47) to stabilize the extracellular matrix; transforming growth factor-(3 (Yamaguchi, Y., Mann, D.
M. and Ruoslahti, E. (1990) Negative regulation of transforming growth factor-beta by the proteoglycan decorin. Nature 346, 281-284; Hildebrand, A., Romaris, M., Rasmussen, L.
l0 M., Heinegard, D., Twardzik, D. R., Border, W. A. and Ruoslahti, E. (1994) Interaction of the small interstitial proteoglycans biglycan, decorin and fibromodulin with transforming growth factor beta. Biochem J 302 ( Pt 2), 527-534) to regulate growth; and hepatocyte growth factorlscatter factor (Lyon, M., Deakin, J. A., Mizuno, K., Nakamura, T. and Gallagher, J. T. (1994) Interaction of hepatocyte growth factor with heparan sulfate. Elucidation of the major heparan sulfate structural determinants. J
Biol Chem 269, 11216-11223; Lyon, M., Deakin, J. A., Rahmoune, H., Fernig, D. G., Nakamura, T.
and Gallagher, J. T. (1998) Hepatocyte growth factor/scatter factor binds with high affinity to dermatan sulfate. J Biol Chem 273, 27I-278) to spur cellular proliferation and organogenesis. In a growing number of instances, it has also been established that there 2o is sequence-specificity in GaIAG-protein interactions in terms of the precise modifications in the chemical structure of GaIAGs that bind with high affinity to a given protein (Mascellani, G., Liverani, L., Bianchini, P., Parma, B., Torri, G., Bisio, A., Guerrini, M. and Casu, B. (1993) Structure and contribution to the heparin cofactor II-mediated inhibition of thrombin of naturally oversulphated sequences of dermatan sulphate. Biochem J 296 ( Pt 3), 639-648; Maimone, M. M. and Tollefsen; D. M.
(199I) Structure of a dermatan sulfate hexasaccharide that binds to heparin cofactor II with high affinity. J Biol Chem 266, 14830.) Further, manipulation of GAG chemical structure has been shown to promote anti-tumor activities, inhibiting angiogenesis and tumor metastasis (Denholm, E. M., Lin, Y. Q, and Silver, P. J. (2001) Anti-tumor activities of 3o chondroitinase AC and chondroitinase B: inhibition of angiogenesis, proliferation and invasion. Eur J Pharmacol 416, 2I3-221.) Modification of CS-containing proteoglycans has been observed in a variety of human cancers including those of the colon (Iozzo, R.
V. and Cohen, I_ (1993) Altered proteoglycan gene expression and the tumor stroma.
Experientia 49, 447-455; Makatsori, E., Lamari, F. N., Theocharis, A. D., Anagnostides, S., Hjerpe, A., Tsegenidis, T. and Karamanos, N. K. (2003) Large matrix proteoglycans, versican and perlecan, are expressed and secreted by human leukemic monocytes.
Anticancer Res 23, 3303-3309), blood (Makatsori, E., Larnari, F. N., Theocharis, A. D., Anagnostides, S., Hjerpe, A., Tsegenidis, T. and Karamanos, N. K. (2003) Large matrix proteoglycans, versican and perIecan, are expressed and secreted by human leukemic monocytes. Anticancer Res 23, 3303-3309), and larynx (Papadas, T. A., Stylianou, M., Io Mastronikolis, N. S., Papageorgakopoulou, N., Skandalis, S., Goumas, P., Theocharis, D.
A. and Vynios, D. H. (2002) Alterations in the content and composition of glycosaminoglycans in human laryngeal carcinoma. Acta Otolaryngol 122, 330-337.) Defined GalAG oligosacchanides are also being developed as therapeutics for blood coagulation disorders (Vicente, C. P., Zancan, P., Peixoto, L. L., Alves-Sa, R., Araujo, F.
S., Mourao, P. A. and Pavao, M. S. (2001) Unbalanced effects of dermatan sulfates with different sulfation patterns on coagulation, thrombosis and bleeding. Thromb Haemost 86, 1215-1220; Gandra, M., Cavalcante, M. and Pavao, M. (2000) Anticoagulant sulfated glycosaminoglycans in the tissues of the primitive chordate Styela plicate (Tunicata).
Glycobiology 10, 1333-1340.) Thus, the characterization of structure-function 2o relationships involving GalAGs helps with the understanding of their biological roles.
The structural characterization of complex acidic polysaccharides, like GAGS, is a challenging task. Due to their complex non-template based biosynthesis, it has been difficult to develop methodologies to obtain sufficient material containing pure GAG
oligosaccharides. Further, the chemical heterogeneity and highly acidic nature of GAGS
have complicated their analysis. Significant advances have been made in the development of enzymatic tools to depolymerize GAGS at specific linkages.
Analytical tools such as mass spectrometry (Rhomberg, A. J., Ernst, S., Sasisekharan, R.
and Biemann, K. (1998) Mass spectrometric and capillary electrophoretic investigation of the enzymatic degradation of heparin-Like glycosaminoglycans. Proc Natl Acad Sci U
S A
95, 4176-4181), capillary electrophoresis (Rhomberg, A. J., Ernst, S., Sasisekharan, R.
and Biemann, K. (1998) Mass spectrometric and capillary electrophoretic investigation of the enzymatic degradation of heparin-like glycosaminoglycans. Proc Natl Acad Sci U
S A 95, 4176-4181 } and NMR (Guernni, M., Raman, R., Venkataraman, G., Torri, G., Sasisekharan, R. and Casu, B. (2002) A novel computational approach to integrate NMR
spectroscopy and capillary electrophoresis for structure assignment of heparin and heparan sulfate oIigosaccharides. Glycobiology 12, 713-719) have also been useful for accurate structural characterization of GAGS using very small amounts of material that are typically isolated from tissues. Enzymatic tools, when used in conjunction with analytical methods, have allowed for the rapid and precise sequencing of biologically relevant GAGS (Venkataraman, G., Shriver, Z., Raman, R. and Sasisekharan, R.
(1999) to Sequencing complex polysaccharides. Science 286, 537-542.) Various microorganisms express GAG-degrading polysaccharide lyases.
Mechanistically, these lyases degrade their substrates via a (3-elimination reaction that generates products with an unsaturated 4, 5 bond on the uronic acid at the site of cleavage. Extensive biochemical characterization of the activity and substrate specificity Z5 of some of these enzymes, such as the heparinases, have successfully enabled their utilization as tools for structural characterization of heparin and heparan sulfate GAGS
{HSGAGs) (Venkataraman, G., Shriven Z., Raman, R. and Sasisekharan, R. (1999) Sequencing complex polysaccharides. Science 286, 537-542; Ernst, S., Rhomberg, A. J., Biemann, I~. and Sasisekharan, R. (1998) Direct evidence for a predominantly exolytic 20 processive mechanism for depolymerization of heparin-like glycosaminoglycans by heparinase I. Proc Natl Acad Sci U S A 95, 4182-4187.) The GaIAG-processing (also referred to as GaIAG-degrading enzymes) enzymes include chondroitinase AC
(cAC, EC

4.2.2.5) chondroitinase B (cB) from Flavobacterium lzepariraum (now known as PedobacteY' heparinus), chondroitinase ABC I (cABC I), ABC II (cABC II, EC
4.2.2.4) 25 from Prvteus vulgaris and hyaluronidase. Chondroitinase AC shows activity against C4S and C6S, while chondroitinase B cleaves DS as its sole substrate.
Chondroitinase ABG I and cABC II process a variety of substrates including C4S, C6S, DS, and hyaluronan. Particularly striking is the ability of these broad substrate specificity enzymes (cABC I and II) to process GaIAGs containing either uronic acid epimer.
3o As introduced above, chondroitinase ABC I is a glycosaminoglycan (GAG) degrading enzyme that selectively depolymerizes chondroitin sulfate (GS) and dermatan sulfate (DS) substrates, as well as unsulfated chondroitin and hyaluronan, albeit at lower rates. Chondroitinase ABC I has been demonstrated to have utility in the analysis of CS/DS and hyaluronan oligosaccharides both from commercial sources and from biologically relevant cell and tissue model systems. In addition, it has been suggested that chondroitinase ABC I may play a direct role as a therapeutic in various clinical conditions. Specifically, chondroitinase ABC I has shown promise in promoting functional recovery through neuro-regenerative activities. In fact, chondroitinase ABC I
has recently been employed as a potential nerve regeneration therapeutic for spinal cord injury (Bradbury, E. J., Moon, L. D., Popat, R. J., King, V. R., Bennett, G.
S., Patel, P.
i0 N., Fawcett, J. W. and McMahon, S. B. (2002) Chondroitinase ABC promotes functional recovery after spinal cord injury. Nature 4I6, 636-640.) Additionally, it was reported that chondroitin sulfate chains are inhibitory to axon regeneration, providing a physical obstacle for this healing process (Morgenstern, D. A., Asher, R. A. and Fawcett, 3. W.
(2002) Chondroitin sulphate proteoglycans in the CNS injury response. Prog Brain Res 137, 313-332.) Furthermore, degradation of these inhibitory GaIAG chains present in the glial scar was shown to impart some level of restoration of physical function in an in vivo mouse model. Understanding the mechanism of action of cABC I, therefore, improve its use as biochemical tool for studying GaIAG structure and advance its therapeutic potential in treatment of medical conditions.
2o Chondroitinase ABC I and chondroitinase ABC II (EC 4.2.2.4) (Hamai, A., Hashimoto, N., Mochizuki, H., Kato, F., Makiguchi, Y., Horie, K. and Suzuki, S. (1997) Two distinct chondroitin sulfate ABC lyases. An endoeliminase yielding tetrasaccharides and an exoeliminase preferentially acting on oligosaccharides. J Biol Chem 272, 9123-9130) are two related enzymes with broad substrate specificity produced by the bacterium Proteus vulgaris. These enzymes depolymerize a variety of GAG
substrates, including chondroitin-4-sulfate (C4S), dermatan sulfate (DS), chondroitin-6-sulfate (C6S), and hyaluronic acid. These enzymes have previously been purified and studied (Hamai, A., Hashimoto, N., Mochizulci, H., Kato, F., Makiguchi, Y., Horie, K.
and Suzuki, S. (1997) Two distinct chondroitin sulfate ABC lyases. An endoeliminase 3o yielding tetrasaccharides and an exoeliminase preferentially acting on oligosaccharides. J
Biol Chem 272, 9123-9130.) Chondroitinase ABC I is a 997 amino acid residue endolytic enzyme that cleaves GAG substrates to tetrasaccharides and disaccharides. It degrades GaIAGs regardless of the CS epimerization state of the uronic acid.
This is particularly notable, as cABC I processes DS despite having little sequence or structural homology when compared with chondroitinase B (cB} (Huang, W., Matte, A., Li, Y., Kim, Y. S., Linhardt, R. J., Su, H. and Cygler, M. (1999) Crystal structure of chondroitinase B from Flavobacterium heparinum and its complex with a disaccharide product at 1.7 A resolution. J Mol Biol 294, 1257-1269.) The crystal structure of cABC
I (Huang, W., Lunin, V. V., Li, Y., Suzuki, S., Sugiura, N., Miyazono, H. and Cygler, M.
(2003} Crystal structure of Proteus vulgaris chondroitin sulfate ABC lyase I
at 1.9A
to resolution. J Mol Biol 328, 623-634) reveals that it has three major domains and indicates that this enzyme shares considerable structural homology with F.
hepa~iyauna chondroitinase AC (cAC) (Fethiere, J., Eggimann, B. and Cygler, M. (1999) Crystal structure of chondroitin AC lyase, a representative of a family of glycosaminoglycan degrading enzymes. J Mol Biol 288, 63S-647), although there is little sequence identity t5 between the enzymes.
Discrepancies in past cloned sequences of cABC I have augmented confusion in studying this enzyme (Sato, N., Shimada, M., Nakajima, H., Oda, H. and Kimura, S.
( 1994) Cloning and expression in Escherichia coli of the gene encoding the Proteus vulgaris chondroitin ABC lyase. Appl Microbiol Biotechnol 41, 39-46; Ryan, M.
J., 2o Khandke, K. M., Tilley, B. C. and Lotvin, J. A. (1994), (international application published under the patent cooperation treaty) WO 94/25567.) Moreover, the cloning and expression of cABC I is challenging because of its size, stability and solubility. In addition to the difficulty of obtaining a pure recombinant protein, the broad substrate specificity complicates elucidation of mechanism as it is unclear how this GAG
lyase is 25 able to process such a broad range of substrates. Provided herein is the sub-cloning of cABC I from Proteus vulgaris and a facile methodology for the recombinant expression and purification of this enzyme (a one-step purification of the pure protein).
Namely the use of a 6x-His tag and a Ni2+ affinity column that allows enzyme purification from crude extract in one chromatography step. The originally expressed cABC I
clone 3o resulted in an enzyme with low activity against a variety of GaIAG
substrates.
Sequencing of the cABC I clone revealed four point mutations at issue with the electron density data of the cABC I crystal structure. Site-directed mutagenesis produced a clone with restored GalAG-degrading function. The enzyme was characterized biochemically, including an analysis of its substrate specificity, an activity assessment and a product profile determination of the recombinant enzyme against a spectrum of GAG
substrates.
By coupling structural inspections of cABC I and an evaluation of sequence homology against other GAG-degrading lyases, a set of amino acids was chosen for further study.
Mutagenesis studies of these residues resulted in the first experimental evidence of cABC I's active site as well as the residues that are important for catalytic activity.
Chondroitinase ABC I was sub-cloned from Protez~s vulgaf~is into an E. coli-based recombinant expression system without its N-terminal leader sequence, expressed and purified to homogeneity using the N-terminal 6X His tag. Sequence analysis of the cloned gene revealed four point mutations (Thr154A1a, Va1309I1e, Pro322Leu, and Pro694G1u) in the DNA sequence that led to signiftcantly diminished enzymatic activity.
These mutations were restored using PCR site-direct mutagenesis (SDM) leading to a fully functional, highly active recombinant chondroitinase ABC I. This enzyme was then characterized in terms of its structural stability, substrate specificity, product profile, and kinetics of action on a variety of GAG substrates. Understanding the mode of action of cABC I and its engineered variants will facilitate the structure-function characterization of biomedically-relevant GAGs/GaIAGs and provide for the 2o development of therapeutics, including therapeutics for nerve regeneration, cancer, etc.
Provided herein, therefore, is the recombinant expression of chondroitinase ABC I and a variety of engineered mutants thereof for the treatment of various pathologies.
It has been determined that on opposing sides of the catalytic cleft are substrate speciftc residues. His388 and His389 (residue numbering is consistent with the numbering prevalently used in the literature) are important for dermatan sulfate (DS) processing, and when mutated (to alanine, lysine or arginine) has activity against chondroitin-6-sulfate (C6S) and chondroitin-4-sulfate (C4S), and not DS (like chondroitinase AC). On the opposing cleft, Arg560 is important for C4S and C6S
processivity; modification of this residue (such as to alanine or lysine) results in a DS-3o exclusive enzyme (like chondroitinase B). Further mutagenesis, in the form (for example) of a double or triple mutant, may also result in modified cABC I
enzymes that have a different set substrate specificities, or an altered product profile.
Additionally, specificity for hylauronan-based GAGs could be conserved in cABC I mutants;
alternatively, activity against these GAGS could be engineered out, so as to provide a means to selectively alter specific parts of the extracellular matrix (cABC I
processes galactosaminoglycans including C4S, C6S, dermatan sulfate, and modified GalAGs such as chondroitin D and chondroitin E; cABC I also processes the glucosaminoglycan hyaluronan}. There are a number of other residues which play some role in regulating substrate specificity. Tyr392 is important in this way. His561 and Asn587 interact with l0 the 4-O-sulfate of GaIMTAC4S. Arg500Lys and Arg221A1a provide C6S selective enzymes; Arg500G1n provides a C4S selective enzyme. Tyr508Phe and Arg560-based mutants provide altered product profiles, including yielding higher order products.
Therefore the mutants provided can be selected for the regulation of substrate specificity and the generation of unique, novel, or difficult-to-attain product profiles.
In one aspect of the invention a method of recombinantly expressing chondroitinase ABC I is provided. In another aspect of the invention a method for purifying a recombinantly expressed chondroitinase ABC I is provided. Also provided are the chondroitinase ABC I enzymes themselves. The nucleic acid and amino acid sequence of a cABC I enzyme provided herein is provided as SEQ ID NO: 1 and SEQ ID
2o NO: 2, respectively. Additionally, also provided axe polypeptides that comprise the amino acid sequence of SEQ ID NO: 2 and fragments thereof. The fragment can be of any size greater than 7 amino acids in length. In some embodiments the fragment is at least 10, 15, 20, 30, 50, 75, 125, 100, 154, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 950, 975, 990 or moxe amino acids in length.
The chondroitinase ABC I enzymes provided also include modified chondroitinase ABC I enzymes. Such enzymes include those that can contain amino acid substitutions (e.g., at one or more of the important amino acid residues) of native chondroitinase ABC I as provided herein. The chondroitinase ABC I enzymes provided can have altered enzymatic activity and/or substrate specificity as compared to a native 3o chondroitinase ABC I. In some embodiments, the chondroitinase ABC I enzymes have increased enzymatic activity. In others, the chondroitinase ABC I enzymes have diminished enzymatic activity.
As used herein a "native chondroitinase ABC I" refers to a chondroitinase ABC
I
enzyme that would be found in nature. Examples of native chondroitinase ABC I
enzymes, therefore, include, chondroitinase ABC I enzymes with an amino acid sequence of any of SEQ ID NOs: 1-10, 14, 1 S and 22-24. Native cABC I also include the enzymes represented by, for example, those sequences found in the following:
GenBank Accession Numbers 1HN0 A, I29953, PS9807 and gi:30749254; SEQ ID
NOs: 2 and 6 of 5,578,480; SEQ ID NOs: 2 and S of PCT/LJS94/04495; and Sato et al., 1o Appl. Microbiol. Biotechnol. (1994) 41:39-46. Sequences derived from proteins extracted from cultures of, for example native Proteus vulgaris are considered within the definition of native cABC I, including those sequences that were derived from native cultures but contain sequencing errors.
Native chondroitinase ABC I enzymes, therefore, differ from "modified is chondroitinase ABC I enzymtes", which are chondroitinase ABC I enzymes that are not as they would be found in nature and are somehow altered or modified. As used herein the "sequence of a modified chondroitinase ABC I" is intended to include the sequences of the modified enzymes provided with conservative substitutions therein and functional equivalents thereof, including, but not limited to fragments of the enzymes.
These 2o sequences in some embodiment include the signal sequence. In other embodiments the signal sequence is not included. In one embodiment, the cABG I enzymes provided, such as the modified chondroitinase ABC I enzymes, do not include those with an amino acid sequence as provided in any of SEQ ID NOs: 3-24. In instances where the term "chondroitinase ABC I" is used without the terms "native" or "modified" the term is 25 intended to refer to both native and modified cABC I enzymes. Modified chondroitinase ABG I enzymes can be produced using conservative substitutions, nonconservative substitutions, deletions, additions or a multiple mutant combination.
In some embodiments, the modified chondroitinase ABC I enzymes have a modified product profile. A "modified product profile" is the set of products that results 3o from the interaction of the modifzed chondroitinase ABC I enzymes with a polysaccharide or group of polysaccharides in a sample. The "set of products"
is the number and kind of xesulting reaction products. The modified product profile differs from a "native product profile" in that the riative product profile is the set of products that results from the interaction of native chondroitinase ABC I enzyme with a polysaccharide or group of polysaccharides. In order to compare a native product profile with a modified product profile, the number and kind of resulting reaction products are compared under the same experimental conditions with the same polysaccharide or group of polysaccharides.
Therefore, in some aspects of the invention modified chondroitinase ABC I
1o enzymes are provided that have a modified product profile that is at least IO% different than the modified product profile of a native chondroitinase ABC T. In some embodiments the product profile differs from that of the native enzyme by at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or more. The difference between two product profiles can be quantitated in a variety of ways. For example, the number of a particular saccharide reaction product can be compared, the number of all reaction products can be compared, the number of kinds of reactions products can be compared, or some combinations of these values, etc. In one embodiment the product profiles are determined from the interaction of the er~zymes on a galactosaminoglycan, such as chondroitin sulfate. In other embodiments the product pxofiles are determined from the 2o interaction of the enzymes on dermatan sulfate. In one embodiment the product profiles are determined with capillary electrophoresis. In other embodiments the product profiles are determined with a combination of capillary electrophoresis and mass spectrometry, e.g., MALDI-MS. Other ways to compare the product profiles are known to those of ordinary skill in the art.
A published crystal structure of chondxoitinase ABC I was used as a template for the design of active site mutants. The properties of the resulting enzymes were studied in an attempt to determine the importance of individual amino acid residues for enzymatic activity. His501, Tyr508, Arg560 and G1u653 were all mutated to alanine using SDM, recombinantly expressed and characterized. The inactivity of all of these 3o mutants confirmed their role in the catalytic activity of chondroitinase ABC I.

Therefore, in one aspect of the invention modified chondroitinase ABC I
enzymes are provided which contain His501, Tyr508, Arg560 or G1u653 or some combination thereof and at least one amino acid substitution. The at least one amino acid substitution is, in one embodiment, a substitution of a residue other than the residue or set of residues chosen from His501, Tyr508, Arg560 and G1u653 to be maintained. Tn another aspect of the invention a modified chondroitinase ABC Z is provided wherein the amino acid sequence of the modified enzyme contains at least one amino acid residue that has been substituted with a different amino acid residue than in native chondroitinase ABC I and wherein the residue that is substituted is His501, TyrS08, Arg560 or G1u653.
In some 1o embodiments the different amino acid is not alanine.
In addition to these residues, another set of amino acids that were potentially important in substrate binding, substrate positioning, catalysis, and product release were identified. Mutating His388 and His389 to alanine, lysine, or arginine resulted in an enzyme that can process chondroitin 4-sulfate and 6-sulfate, but not DS.
Mutating Arg560 to alanine or lysine resulted in an enzyme that exclusively degrades DS.
Mutating Arg500 to lysine resulted in an enzyme that degrades chondroitin 6-sulfate as its sole substrate, similar to chondroitinase C. Finally, mutating Arg500 to glutamine resulted in an enzyme that selectively degrades chondroitin 4-sulfate, an enzymatic specificity that has not been previously described. Therefore, a diversity of rationally 2o site-directed mutants of chondroitinase ABe T were created that demonstrate significantly altered substrate specificity and reaction kinetics. These mutant enzymes will be valuable as both tools for studying structure-function relationships of GAGS as well as therapeutics for tailoring the GAG profile in specific diseases, such as nerve injury; stroke; epithelial disease; viral, bacterial and pathogenic infection;
and cancer.
Therefore, in one aspect of the invention chondroitinase ABC I enzymes are provided that have altered substrate specificity. These chondroitinase ABG I
enzymes can be used to selectively degrade certain polysaccharides. As used herein, "degrade"
refers to any action of an enzyme on a polysaccharide that results in its modification or cleavage. "Polysaccharide-degrading enzymes", therefore, refer to any enzyme that 3o degrades a polysaccharide. Such enzymes include glycosaminoglycan-degrading enzymes. "Glycosaminoglycan-degrading enzymes" refer to enzymes that degrade a glycosaminoglycan and include, for example, heparinase I, heparinase II, heparinase III, d4,5 glycuronidase, 2-O sulfatase, 3-O sulfatase, 6-O sulfatase, N-sulfatase, chondroitinase, hyaluronidase, etc. as well as mutant versions and functional equivalents thereof. "Galactosaminoglycan-degrading enzymes" refer to enzymes that degrade a galactosaminoglycan and include chondroitinase B, chondroitinase AC, chondroitinase ABC I, chondroitianse ABC II, chondro-4 sulfatase, chondro-6 sulfatase, hyaluronidase, etc. as well as mutant versions and functional equivalents thereof. The chondroitinase ABC I enzymes and compositions provided can be used to degrade a polysaccharide (e.g., glycosaminoglycan(s) and/or galactosaminoglycan(s)) isa vitro or iya vivo. The IO degradation can be a result of the use of a chondroitinase ABC I or composition thereof provided herein alone or in combination with at Ieast one other polysaccharide-degrading enzyme. For instance, the at least one other polysaccharide-degrading enzyme can be native or modified versions of any of the enzymes provided herein, which include chondroitinase ABC I, chondroitinase AC, chondroitinase B, chondroitinase ABC
II, etc.
~5 Provided herein is a chondroitinase ABC I that processes chondroitin sulfate and not dermatan sulfate. In another aspect of the invention a chondroitinase ABC
I that selectively degrades dermatan sulfate is provided. In still Qther aspects of the invention a chondroitinase ABC I that selectively degrades chondroitin 6-sulfate is provided. In yet other aspects of the invention a chondroitinase ABC I that selectively degrades 2o chondroitin 4-sulfate is provided. Therefore, modified chondroitinase ABC I
enzymes are provided which include any combination of the amino acid substitutions provided herein. As used herein, "selectively degrades" refers to the enzymes action toward a particular substrate. Selectively degrade is meant to encompass circumstances where an enzyme that acts upon a particular substrate does so at an increased rate as compared to 25 the rate of action on another substrate. The term xs also meant to encompass circumstances where an enzymes degrades one particular substrate or set of substrates exclusively. The term is also intended to encompass situations whereby the enzymes act upon a particular substrate in a way such that one of ordinary skill in the art can observe a preference of action. Therefore, provided herein are cABC I enzymes that exhibit 3o "cAC-like" or "cB-like" activity. Chondroitinase ABC I enzymes that cleave C4S and C6S preferentially are referred to herein as chondroitinase ABC I enzymes with cAC-like activity. Similarly, cABC I enzymes that preferentially cleave DS are referred to herein as chondroitinase ABC I enzymes with cB-like activity.
One of ordinary skill in the art is enabled, in Iight of the present disclosure, to produce chondroitinase ABC I enzymes by standard technology, including recombinant technology, direct synthesis, mutagenesis, etc. A number of native sequences of chondroitinase ABC I are provided herein (e.g., SEQ ID NOs: 1 and 2; GenBank Accession number P59807, which provides the amino acid sequence for chondroitin ABC Iyase I precursor (the mature chain is given as amino acids 25-1021 of the precursor sequence), See also Ryan et al. (Ryan, M. J., Khandke, K_ M., Tilley, B. C. and Lotvin, J. A. (1994), WO 94/25567.) One may produce a modified chondroitinase ABC
I having an amino acid sequence of the peptide of a native chondroitinase ABC
I, wherein at least one residue at position 105, 131, 154, 218, 219, 22 l, 222, 253, 2?6, 286, 309, 312, 322, 388, 389, 392, 439, 442, 444, 490, 500, 501, 508, 560, 561, 587, 653, 678, 694 or 712 has been substituted or deleted.
One of skill in the art may also substitute appropriate codons to produce the desired amino acid substitutions by standard site-directed mutagenesis techniques. It is possible to use any sequence which differs from the nucleic acid equivalents of the sequences of chondroitinase ABC I only due to the degeneracy of fhe genetic code as the starting point for site directed mutagenesis. The mutated nucleic acid sequence may then be Iigated into an appropriate expression vector arid expressed in a host such as F.
hepezrihmn or E. coli. The resultant chondroitinase ABC I may then be purified by techniques provided herein and/or known by those of ordinary shill in the art.
One of ordinary skill in the art is also enabled in light of the present disclosure to produce modified chondroitinase ABC enzymes having an amino acid sequence of native chondroitinase ABC or conservative substitutions thereof, wherein at least one of the residues at a position selected from 105, 131, 154, 218, 219, 221, 222, 253, 276, 286, 309, 312, 322, 388, 389, 392, 439, 442, 444, 490, 500, 501, 508, 560, 561, 587, 653, 678, 694 or 712 is maintained. These modified chondroitinase ABC I enzymes further contain at least one amino acid substitution. In some embodiments these amino acid 3o substitutions are in portions of the enzymes that have not been shown to be important to catalysis, substrate binding, calcium coordination, etc. In other embodiments the at least one amino acid substitution is of one of the residues listed above provided that it is not a substitution of the residue or residues that are maintained. In some embodiments, the modified chondroitinase ABC enzymes contain 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, Z I, 22, 23, 24, 25, 30, 40, 50 or more substitutions.
Mutations can be made by selecting an amino acid substitution, or by random mutagenesis of a selected site in a nucleic acid which encodes the polypeptide. Modified polypeptides are then expressed and tested for one or more activities to determine which mutation provides a modified polypeptide with the desired properties.
Methods for making amino acid substitutions, additions or deletions are well known in the art. The terms "conservative substitution", "non-conservative substitutions", "non-polar amino acids", "polar amino acids", and "acidic amino acids"
are all used consistently with the prior art terminology. Each of these terms is well-known in the art and has been extensively described in numerous publications, including standard biochemistry text books, such as "Biochemistry" by Geoffrey Zubay, Addison-Wesley Publishing Co., 1986 edition, which describes conservative and non-conservative substitutions, and properties of amino acids which lead to their definition as polar, non-polar or acidic.
One type of amino acid substitution is referred to as a "conservative substitution."
As used herein, a "conservative amino acid substitution" or "conservative substitution"
2o refers to an amino acid substitution in which the substituted amino acid residue is of similar charge as the replaced residue and is of similar or smaller size than the replaced residue. Conservative substitutions of amino acids include substitutions made amongst amino acids within the following groups: (a) the small non-polar amino acids, A, M, I, L, and V; (b) the small polar amino acids, G, S, T and C; (c) the amido amino acids, Q and N; (d) the aromatic amino acids, F, Y and W; (e) the basic amino acids, K, R
and H; and (f) the acidic amino acids, E and D. Substitutions which are charge neutral and which replace a residue with a smaller residue may also be considered "conservative substitutions" even if the residues are in different groups (e.g., replacement of phenylalanine with the smaller isoleucine). The term "conservative amino acid 3o substitution" also refers to the use of amino acid analogs or variants.

Additionally, some of the amino acid substitutions are non-conservative substitutions. Non-conservative substitutions, such as between, rather than within, the above groups (or two other amino acid groups not shown above), which will differ more significantly in their effect on maintaining (a) the structure of the peptide backbone ~n the area of the substitution (b) the charge or hydrophobicity of the molecule at the target site, or (c) the bulk of the side chain.
The modified chondroitinase ABC I can have specific substitutions in specified portions of the peptide. In addition to these substitutions which may be conservative or non-conservative, other regions of the peptide may include substitutions that do not to impact the activity of the modified chorfdroitinase ABC I. Therefore, in some embodiments, the nonconservative or cor~servative substitutions are introduced at residues that are remote from, for instance, the catalytic, substrate binding and/or calcium coordination motif residues as provided herein. One skilled in the art will appreciate that the effect of a particular substitution can be evaluated by routine screening assays, preferably the biological assays described herein.
In some embodiments the chondroitir~ase ABC I is in substantially pure form.
dues used herein, the term "substantially pure" means that the proteins are essentially free of other substances to an extent practical arid appropriate for their intended use. In particular, the proteins are sufficiently pure and are sufficiently free from other 2o biological constituents of their hosts cells so as to be useful in, for example, protein sequencing, or producing pharmaceutical preparations. Polypeptides can be isolated from biological samples, and can also be expressed recombinantly in a variety of prokaryotic and eukaryotic expression systems by constructing an expression vector appropriate to the expression system, introducing the expression vector into the expression system, and isolating the recombdnantly expressed protein.
Polypeptides can also be synthesized chemically using well-a stablished methods of peptide synthesis. In some embodiments, chondroitinase ABC I in a substantially purified recombinant form is a preparation of chondroitinase ABC I which has been recombinantly synthesized and which is greater then 90% free of contaminants. Preferably, the material is greater than 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or even greater then 99% free of contaminants. The degree of purity may be assessed by means known in the art.

As used herein with respect to polypeptides, "isolated" means separated from its native environment and present in sufficient quantity to permit its identification or use.
Isolated, when referring to a protein or polypeptide, means, for example: (i) selectively produced by expression cloning or (ii) purified as by chromatography or electrophoresis.
Isolated proteins or polypeptides may be, but need not be, substantially pure.
Because an isolated polypeptide rnay be admixed with a pharmaceutically acceptable carrier in a pharmaceutical preparation, the polypeptide may comprise only a small percentage by weight of the preparation. The polypeptide is nonetheless isolated in that it has been separated from the substances with which it rnay be associated in living systems, i.e., isolated from other proteins.
A "modified chondroitinase ABC I polypeptide" is a polypeptide which contains one or more modifications to the primary amino acid sequence of a chondroitinase ABC
I polypeptide. The modz~ed chondroitinase ABC I polypeptide can contain 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30 or more modifications. Modifications which create a modified chondroitinase ABC I polypeptide may be made recombinantly to the nucleic acid which encodes the modified chondroitinase ABC I polypeptide, and can include deletions, point mutations, truncations, amino acid substitutions and addition of amino acids or non-amino acid moieties to (as described herein): 1) alter enzymatic activity; 2) provide a novel activity or property to a chondroitinase ABC I polypeptide, such as addition of a detectable moiety; or 3) to provide equivalent, greater or lesser interaction with other molecules (e.g., chondroitin sulfate and dermatan sulfate).
Alternatively, modifications can be made directly to the polypeptide, such as by cleavage, and the like.
Modifications also embrace fusion proteins comprising all or part of the chondroitinase ABC I amino acid sequence.
Fusion proteins are also provided in which a chondroitinase ABC I is in a conjugate form with, for example, a targeting molecule. Fusion proteins provide a strategy for the efficacious delivery of an enzyme, e.g., cABC I, and would entail its coupling, via recombinant molecular biotechnology, to a peptide that could deliver the enzyme-targeting molecule unit to a therapeutic target. For example, a peptide fragment 3o responsible for transport to a site within the central nervous system could be developed from a clostridia) neurotoxin, such as tetanus toxin. The coupling of this fragment, without its pathogenic portion, to an enzyme would result in the efficacious therapy of, for example, stroke or spinal cord injury. Additionally, an enzyme could be delivered along with another molecule to provide a joint therapy. For example, the administration of a growth factor from the FGF family along with a chondroitinase agent could provide additional benefit in the treatment of spinal cord injury or stroke. Targeting molecules, therefore, include cancer antigens or portions thereof and pathogen toxins or portions thereof (e.g., tetanus toxin fragment, H~), and conjugates of targeting molecules with cABC I axe also provided.
According to the invention, isolated nucleic acid molecules that code fox a l0 chondroitinase ABC I polypeptide are provided and include: (a) nucleic acid molecules which hybridize under stringent conditions to the nucleic acid equivalent which codes for a chondroitinase ABC I polypeptide as described herein or parts thereof, (b) deletions, additions and substitutions of (a) which code for a respective chondroitinase ABC I
polypeptide or parts thereof, (c) nucleic acid molecules that differ from the nucleic acid molecules of (a) or (b) in codon sequence due to the degeneracy of the genetic code, and (d) complements of (a), (b) or (c).
In certain embodiments, the nucleic acid molecule that codes for a chondroitinase ABC I is highly homologous to the nucleic acid molecules described herein.
Preferably the homologous nucleic acid molecule comprises a nucleotide sequence that is at least 2o about 90% identical to the nucleotide sequence provided herein. More preferably, the nucleotide sequence is at Least about 95% identical, at least about 97%
identical, at least about 98% identical, or at least about 99% identical to the nucleotide sequence provided herein. The homology can be calculated using various, publicly available software tools well known to one of ordinary skill in the art. Exemplary tools include the BLAST
system available from the website of the National Canter for Biotechnology Information (NCBI) at the National Institutes of Health.
As used herein with respect to nucleic acids, the term "isolated" means: (i) amplified in vitro by, for example, polymerase chain reaction (PCR); (ii) recombinantly produced by cloning; (iii) purified, as by cleavage and gel separation; or (iv) synthesized 3o by, for example, chemical synthesis. An isolated nucleic acid is one which is readily manipulable by recombinant DNA techniques well known in the art. Thus, a nucleotide sequence contained in a vector in which 5' and 3' restriction sites are known or for which polymerase chain reaction (PCR) primer sequences have been disclosed is considered isolated but a nucleic acid sequence existing in its native state in its natural host is not.
An isolated nucleic acid may be substantially purified, but need not be. For example, a nucleic acid that is isolated within a cloning or expression vector is not pure in that it may comprise only a tiny percentage of the material in the cell in which it resides. Such a nucleic acid is isolated, however, as the term is used herein because it is readily manipulable by standard techniques known to those of ordinary skill in the art.
Optionally the chondroitinase ABC I is recombinantly produced. Such molecules to may be recombinantly produced using a vector including a coding sequence operably joined to one or more regulatory sequences. As used herein, a coding sequence and regulatory sequences are said to be "operably joined" when they are covalently linked in such a way as to place the expression or transcription of the coding sequence under the influence or control of the regulatory sequences. If it is desired that the coding sequences be translated into a functional protein the coding sequences are operably joined to regulatory sequences. Two DNA sequences are said to be operably joined if induction of a promoter in the 5' regulatory sequences results in the transcription of the coding sequence and if the nature of the linkage between the two DNA sequences does not (1) result in the introduction of a frame-shift mutation, (2) interfere with the ability of 2o the promoter region to direct the transcription of the coding sequences, or (3) interfere with the ability of the corresponding RNA transcript to be translated into a protein.
Thus, a promoter region would be operably joined to a coding sequence if the promoter region were capable of effecting transcription of that DNA sequence such that the resulting transcript might be translated into the desired protein or polypeptide.
The precise nature of the regulatory sequences needed for gene expression may vary between species or cell types, but shall in general include, as necessary, 5' non-transcribing and 5' non-translating sequences involved with initiation of transcription and translation respectively, such as a TATA box, capping sequence, CART sequence, and the like. Especially, such 5' non-transcribing regulatory sequences 3o will include a promoter region which includes a promoter sequence for transcriptional control of the operably joined, gene. Promoters may be constitutive or inducible.

Regulatory sequences may also include enhancer sequences or upstream activator sequences, as desired.
As used herein, a "vector" may be any of a number of nucleic acids into which a desired sequence may be inserted by restriction and ligation for transport between different genetic environments or for expression in a host cell. Vectors are typically composed of DNA although RNA vectors are also available. Vectors include, but are not limited to, plasmids and phagemids. A cloning vector is one which is able to replicate in a host cell, and which is further characterized by one or more endonuclease restriction sites at which the vector may be cut in a determinable fashion and into which l0 a desired DNA sequence may be ligated such that the new recombinant vector retains its ability to replicate in the host cell. In the case of plasmids, replication of the desired sequence may occur many times as the plasmid increases in copy number within the host bacterium, or just a single time per host as the host reproduces by mitosis.
In the case of phage, replication may occur actively during a lytic phase or passively during a lysogenic phase. An expression vector is one into which a desired DNA sequence may be inserted by restriction and ligation such that it is operably joined to regulatory sequences and may be expressed as an RNA transcript. Vectors may further contain one or more marker sequences suitable for use in the identification of cells which have or have not been transformed or transfected with the vector. Markers include, for example, 2o genes encoding proteins which increase or decrease either resistance or sensitivity to antibiotics or other compounds, genes which encode enzymes whose activities are detectable by standard assays known in the art (e.g., 13-galactosidase or alkaline phosphatase), and genes which visibly affect the phenotype of transformed or transfected cells, hosts, colonies or plaques. Preferred vectors are those capable of autonomous replication and expression of the structural gene products present in the DNA
segments to which they are operably joined.
The term "high stringency conditions" as used herein refers to parameters with which the art is familiar. Nucleic acid hybridization parameters may be found in references that compile such methods, e.g. MoleculaY Cloraihg: A Laboratory Manual, J.
Sambrook, et al., eds., Second Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 1989, or CuYrent Protocols ira Molecular Biology, F.M.

Ausubel, et al., eds., John Wiley & Sons, Inc., New York. One example of hig~-stringency conditions is hybridization at 65°C in hybridization buffer (3.5X SSC, 0.02%
Ficoll, 0.02% polyvinyl pyrrolidone, 0.02% Bovine Serum Albumin, 2.Sm~VI
NaH2P04{pH7), 0.5% SDS, 2mM EDTA). SSC is O.15M sodium chloride/O.OI53VI
sodium citrate, pH7; SDS is sodium dodecyl sulphate; and EDTA is ethylenediaminetetracetic acid. After hybridization, a membrane upon which the nucleic acid is transferred is washed, for example, in 2X SSC at room temperature and then at O.I - O.SX SSC/O.1X SDS at temperatures up to 68°C. There are other conditior~s, reagents, and so forth which can be used, which result in the same degree of stringency.
io A skilled artisan will be familiar with such conditions, and thus they are not given here_ The skilled artisan also is familiar with the methodology for screening cells for expression of such molecules, which then are routinely isolated, followed by isolation of the pertinent nucleic acid. Thus, homologs and alleles of the chondroitinase ABC I, as well as nucleic acids encoding the same, may be obtained routinely, and the inventior~ is not intended to be limited to the specific sequences disclosed.
For prokaryotic systems, plasmid vectors that contain replication sites and cont3rol sequences derived from a species compatible with the host may be used.
Examples of suitable plasmid vectors include pBR322, pUCl8, pUCl9 and the like; suitable phage or bacteriophage vectors include 7~gt10, ~,gtll and the like; and suitable virus vectors include pMAM-neo, pI~RC and the like. Preferably, the selected vector of the present invention has the capacity to autonomously replicate in the selected host cell. User ful prokaryotic hosts include bacteria such as E. coli, Flavobacteriurn laeparinurn, Bacillus, Streptonryces, Pseudonaonas, Salrnoraella, Serratia, and the like.
To express the chondroitinase ABC T in a prokaryotic cell, it is desirable to operably join the nucleic acid sequence of a chondroitinase ABC I to a functio~~nal prokaryotic promoter. Such promoter may be either constitutive or, more preferably, regulatable (i.e., inducible or derepressible). Examples of constitutive promoters include the ant promoter of bacteriophage ~,, the bla promoter of the (3-lactamase gene sequence of pBR322, and the CAT promoter of the chloramphenicol acetyl transferase gene sequence of pPR325, and the like. Examples of inducible prokaryotic promoters incl~xde the major right and Ieft promoters of bacteriophage ~, (PL and PR), the trp, recA, lc~cZ, lacl, and gal promoters of E. coli, the a-amylase (LJlmanen et al., J.
Bacteriol. 162:176 182 (1985)) and the ~-28-specific promoters of B. subtilis (Gilman et al., Gezze seqzzezzce 32:11-20 (1984)), the promoters of the bacteriophages of Bacillus (Gryczan, In: The Molecular Biology of the Bacilli, Academic Press, Inc., NY (1982)), and Stz-eptomyces promoters (Ward et al., Mol. Gen. Genet. 203:468-478 (1986)).
Prokaryotic promoters are reviewed by Glick (J. Ind. Microbiol. 1:277-282 (1987)); Cenatiempo (Biochimie 68:505-516 (1986)); and Gottesman (Azzn. Rev.
Genet.
18:415-442 ( 19 84)).
Proper expression in a prokaryotic cell also requires the presence of a ribosome to binding site upstream of the encoding sequence. Such ribosome binding sites are disclosed, for example, by Gold et al. (Anzz. Rev. Microbiol. 35:365-404 (1981)).
Because prokaryotic cells may not produce the chondroitinase ABC I with normal eukaryotic glycosylation, expression of the chondroitinase ABC I in eukaryotic hosts is useful when glycosylation is desired. Preferred eukaryotic hosts include, for example, yeast, fungi, insect cells, and mammalian cells, either in vivo or in tissue culture. Mammalian cells which may be useful as hosts include HeLa cells, cells of fibroblast origin such as VERO or CHO-Kl, or cells of lymphoid origin, such as the hybridoma SP2/0-AG14 or the myeloma P3x63Sg8, and their derivatives. Preferred mammalian host cells include SP2/0 and J558L, as well as neuroblastoma cell lines such 2o as IMR 332 that may provide better capacities for correct post-translational processing.
Embryonic cells and mature cells of a transplantable organ also are useful according to some aspects of the invention.
In addition, plant cells are also available as hosts, and control sequences compatible with plant cells are available, such as the nopaline synthase promoter and polyadenylation signal sequences.
Another preferred host is an insect cell, for example in Drosoplzila larvae.
Using insect cells as hosts, the Drosophila alcohol dehydrogenase promoter can be used (Rubin, Science 240:1453-1459 (1988)). Alternatively, baculovirus vectors can be engineered to express large amounts of the chondroitinase ABC I in insect cells (Jasny, Science 238:1653 (1987); Miller et al., In: Gezzetic Ezzgineering (1986), Setlow, J.K., et al., eds., Plenum, Vol. 8, pp. 277-297).

Any of a series of yeast gene sequence expression systems which incorporate promoter and termination elements from the genes coding for glycolytic enzymes and which are produced in large quantities when the yeast are grown in media rich in glucose may also be utilized. Known glycolytic gene sequences can also provide very efficient s transcriptional control signals. Yeast provide substantial advantages in that they can also carry out post-translational peptide modifications. A number of recombinant DNA
strategies exist which utilize strong promoter sequences and high copy number plasmids which can be utilized for production of the desired proteins in yeast. Yeast recognize leader sequences on cloned mammalian gene sequence products and secrete peptides bearing leader sequences (i.e., pre-peptides).
A wide variety of transcriptional and translational regulatory sequences may be employed, depending upon the nature of the host. The transcriptional and translational regulatory signals may be derived from viral sources, such as adenovirus, bovine papilloma virus, simian virus, or the like, where the regulatory signals are associated with a particular gene sequence which has a high level of expression.
Alternatively, promoters from mammalian expression products, such as actin, collagen, myosin, and the like, may be employed. Transcriptional initiation regulatory signals may be selected which allow for repression or activation, so that expression of the gene sequences can be modulated. Of interest are regulatory signals which are temperature-sensitive so that by varying the temperature, expression can be repressed or initiated, or which are subject to chemical (such as metabolite) regulation.
Chondroitinase ABC I enzymes are useful as an enzymatic tool due to substrate specificity and specific activity. The enzymes are also useful for degrading polysaccharides. The chondroitinase ABC I enzymes may be used to specifically cleave a polysaccharide by contacting the polysaccharide substrate with the chondroitinase ABC I. In some embodiments the chondroitinase ABC I enzymes degrade particular polysaccharide exclusively. The invention is useful in a variety of in vitro, irz vivo and ex vivo methods in which it is useful to degrade polysaccharides.
Compositions with agents in addition to a polysaccharide-degrading enzyme are 3o also useful for degrading polysaccharides, such as glycosaminoglycans. For instance, it has been found that the addition of divalent ions can alter the function of a polysaccharide-degrading enzymes, such as cABC I. The divalent ions can be, but are not limited to, calcium ion, manganese ion, copper ion, iron ion, barium ion, magnesium ion, zinc ion and lanthanides, such as, terbium or lutetium. In one embodiment where it is desirable to inhibit the function of the enzyme the composition can include zinc ion.
The compositions are also meant to encompass combinations of divalent ions.
Where enzyme processivity is desirable, calcium ion, such as in the form of CaCl2, can be included with the enzyme. The CaClz can be at any concentration, for instance, the CaCl2 can be at a concentration of at least l, 2, 3, 4, 5, 6, 7, 8, 9, ar 10 mM or more in a composition. Compositions are also provided wherein the compositions contain enzyme, to divalent ion and a pharmaceutically or physiologically acceptable carrier.
Compositions are also provided whereby the composition contains an enzyme and an enzyme stabilizer. The enzyme stabilizer can be, for example, a protease inhibitor, such as, AEBSF, bestatin, E64 protease inhibitor, pepstatin A ar phosphoramidon. A number of commercially available protease inhibitors and protease inhibitor cocktails are known in the art (e.g., Benzamidine, Protease ArrestT'~ Reagent, Protease Inhibitor Cocktail Set II, Protease Inhibitor Cocktail Set III
(Calbiochem)). The enzyme stabilizer can also be a water mimic, such as, for example, glycerol or dextran.
Compositions are also provided that include an enzyme, enzyme stabilizer and a pharmaceutically or physiologically acceptable Garner.
The compositions and enzymes provided herein can be used for a variety of purposes. Methods of degrading a polysaccharide, such as a glycosaminoglycan, by contacting the glycosaminoglycan with any of the enzymes or compositions provided herein in an amount effective to degrade the glycosaminoglycan, therefore is provided.
As used herein "an amount effective" is one in which one particular agent or a set of agents in a composition produces the desired effect. For example, an amount effective of a composition that contains two enzymes, refers to the amount necessary to obtain a desired effect as a result of the action of one enzyme or the other, or the amount of the two enzymes in combination whereby it is the combination that provides the desired effect. The methods for degrading (i.e., cleaving or modifying the polysaccharide in some way) can include the use of one or more polysaccharide-degrading enzymes that can be placed in contact with one or more polysaccharides. The enzymes that are used can be placed in contact with the polysaccharide at the same time or at different times.
Depending on the action of the enzymes, a specific order of enzymes may be desired.
Encompassed herein is the use of two or more enzymes in any order to degrade a polysaccharide.
Methods for degrading a polysaccharide are also provided whereby the polysaccharide is cleaved by the action of an enzyme in the presence of a divalent ion.
The diavlent ion can be introduced to the reaction at any point before, concomitantly with or after contacting a polysaccharide with a polysaccharide-degrading enzyme.
Divalent ions can result in better processing of a substrate or can result in the inhibition l0 of the processing of a substrate. Therefore, different divalent ions may be used in the method of degrading a polysaccharide. The ions can be used at the same time or can be used at different times to modulate the enzymatic reaction. For instance, a divalent ion, such as calcium may be used to facilitate the reaction, and at some point after, zinc ion may be introduced to the reaction (ions such as zinc can be inhibitory to enzyme function). In some embodiments it is desirable not to use a divalent ion, such as zinc.
The divalent ions can be introduced to the enzymatic reaction in any way such that the reaction is altered in some way. The divalent ions can be placed in contact with the polysaccharide, the polysaccharide-degrading enzyme or both. The divalent ions can include any such ions known in the art including those described herein.
As another way to control polysaccharide degradation reactions, chelators may be used. Therefore, the methods provided can further include the step of introducing a chelator to the enzymatic reaction. Chelators can be introduced to any of the compositions and methods provided. For example, the chelator can be introduced before, concomitantly with or after the introduction of a divalent ion to the reaction. In one embodiment the chelator is EDTA or EGTA.
Methods and compositions are also provided herein where a polysaccharide is processed in the presence of calcium. In one embodiment the cABC I enzyme used in these methods and compositions are those that have had the calcium coordination motif modified in some way. A novel calcium-coordination site in proximity to the enzyme active site has been found. The residues at positions 490, 442, and 444 are important components of this calcium-coordination site. Modulating this site, as well as regulating calcium levels in reaction, are important parts of controlling activity.
Therefore, methods are provided whereby a polysaccharide is degraded with a modified cABC
I, that has had a modification of one or more of these calcium coordination motif residues.
The method can also include the modulation of calcium levels to control the enzymatic reaction driven by the modified cABC I. Compositions are also provided that contain such modified cABC I enzymes as well as varying levels of calcium (e.g., calcium ion in the form of CaCIz).
Methods are also provided for the degradation of a polysaccharide using the enzymes and compositions provided herein in the presence of an enzyme stabilizer. In to one embodiment the enzyme stabilizer is a protease inhibitor, such as AEBSF, bestatin, E64 protease inhibitor, pepstatin A or phosphoramidon. In another embodiment the enzyme stabilizer is a water mimic, such as glycerol or dextran.
There are a number of other ways in which the enzymatic reaction can be controlled. Therefore, compositions and methods are also provided which incorporate the following other agents and their use, respectively. Any of the conditions can be used in any combination to produce the desired enzymatic effect in the methods provided herein. Likewise any combination of agents that control these conditions (e.g., pH
modifying agents, salts, buffer, etc.) can be incorporated in any of the compositions provided. Therefore, combinations of divalent ions and/or enzyme stabilizers with one or more of the following are also specifically contemplated for the methods and compositions provided herein. cABC I enzymes have been analyzed in a variety of reaction conditions. Enzyme-substrate reaction parameters can be chosen to control substrate specificity, the mechanism of action, and/or the product profile.
These reaction parameters include salt (e.g., NaCl, NaAC), temperature, pH, buffer (Tris buffer, or phosphate buffer), and reaction volume. Therefore compositions and methods are provided whereby these reaction parameters or some combination thereof are controlled.
For example, the pH can be controlled. The pH for a reaction or in a composition can be, for example, greater than 7 but less than 8. In other examples, the pH can be less than 9.
The pH can also be 7 or 8. In other examples, the pH can be between 6 and 9 or between 7 and 8. In one embodiment when a phosphate buffer is used and the substrate on which the enzyme acts is chondroitin sulfate, the pH is 7. The pH can be controlled with a pH

modifying agent, such agents are well known to those of skill in the art. Such agents can be added to any of the compositions provided herein, such that the composition has a resulting pH that is desixed.
Methods and compositions are also provided whereby the buffer is controlled.
In some embodiments the buffer is Tris buffer or phosphate buffer.
Methods and compositions where the ionic strength (e.g., salt concentration) is controlled or of a certain concentration are also provided. The salt concentration can be less than 500 mM, Iess than 400 mM or less than 250 mM. The salt concentration can also be between 50-S00 mM, 50-125 mM, 60-125 mM, I25-I50 mM, 100-250 mM, 50-400 mM, 150-400 mM, 100-500 mM or 150-500 mM. 'The salt concentration can also be greater than SO mM, 62.5 mM, 100 mM, 125 mM or 250 mM. The salt can be any of those known in the art and include sodium chloride, sodium acetate, sodium sulfate or ammonium sulfate.
Methods are also provided that include the control of the temperature of the reaction. The temperature can be less than 40°C. The temperature can also be between 25-45°C, between 30-40°C, between 25-40°C, between 30-3?°C, between 38-45°C or between 38-50°C. The temperature can also be 37°C or 40°C.
Analyses of polysaccharides as described in the present disclosure are possible using chondroitinase ABC I alone or in conjunction with other enzymes as well as the compositions provided. Other polysaccharide-degrading enzymes include but are not limited to othex chondroitinases (e.g. chondroitinase AC, chondroitinase B, C, ABC II), lyases (e.g., the two classes of GAG lyases based on structural folds; barrel-like, a5-6/a5-6 topology and right-handed parallel (3-helix fold), hydxolases, chondro-4-sulfatase, chondro-6-sulfatase, hyaluronate lyase, hyaluronidase, heparin hydrolase, heparinase-I, heparinase-II, heparinase-III, keratanase, D-glucuronidase, Delta 4, 5-glycuronidase and L-iduronidase, 2-O sulfatase, pectin lyase, pectate lyase, modified versions of these enzymes, variants and functionally active fragments thereof or combinations thereof. As used herein a "polysaccharide-degrading enzyme" is any enzyme which cleaves or somehow modifies a polysaccharide. The chondroitinase ABC I enzymes provided, 3o when used in conjunction with one or more other enzymes, can be used prior to, subsequent to or concurrent with the use of the one or more other enzymes.

The methods that may be used to test the specific activity of chondroitinase ABC
I include those known in the art. The term "specific activity" as used herein refers to the enzymatic activity of a preparation of chondroitinase ABC I. These methods may also be used to assess the function of variants and functionally active fragments of chondroitinase ABC I. The k~at value may be determined using any enzymatic activity assay to assess the activity of a modified chondroitinase ABC I enzyme.
Several such assays are well-known in the art. For instance, an assay for measuring k~at 1S
described in (Ernst, S. E., Venkataraman, G., Winkler, S., Godavarti, R., Langer, R., Cooney, C.
and Sasisekharan. R. (1996) Biochem. J. 315, 589-597). The "native chondroitinase 1 o ABC I k~at value" is the measure of enzymatic activity of a native chondroitinase ABC I.
The native chondroitinase ABC I can be obtained from cell lysates of P.
vulga~is.
Due to the activity of chondroitinase ABC I on polysaccharides, the product profile produced by a chondroitinase ABC I may be determined by any method known in the art for examining the type or quantity of degradation product produced by chondroitinase ABC I alone or in combination with other enzymes. One of skill in the art will also recognize that the chondroitinase ABC I may also be used to assess the purity of polysaccharides in a sample.
One preferred method for determining the type and quantity of product is described in Rhomberg, A.J.' et al., PNAS, v. 95, p. 4176-4181 (April 1998), which is 2o hereby incorporated in its entirety by reference. The method disclosed in the Rhomberg reference utilizes a combination of mass spectrometry and capillary electrophoretic techniques to identify the enzymatic products produced by heparinase. The Rhomberg study utilizes heparinase to degrade HLGAGs (heparin-like glycosarninoglycans) to produce HLGAG oligosaccharides. MALDI (Matrix-Assisted Laser Desorption Ionization) mass spectrometry can be used for the identification and semiquantitative measurement of substrates, enzymes, and end products in the enzymatic reaction. The capillary electrophoresis technique separates the products to resolve even small differences amongst the products and is applied in combination with mass spectrometry to quantitate the products produced. Capillary electrophoresis may even resolve the 3o difference between a disaccharide and its semicarbazone derivative.

The chondroitinase ABC I enzymes may also be used as a tool to sequence polysaccharides. Detailed methods for sequencing polysaccharides and other polymers are disclosed in co-pending U.S. Patent Applications Serial Nos. 09/557,997 and 09/558,137, both filed on April 24, 2000 and having common inventorship. The entire contents of both applications are hereby incorporated by reference. Briefly, the method is performed by enzymatic digestion, followed by mass spectrometry and capillary electrophoresis. In the example described in the Rhomberg reference, enzymatic reactions are performed by adding 1 microliter of enzyme solution to 5 microliter of substrate solution. The digestion is then carried out at room temperature (22°C), and the l0 reaction is stopped at various time points by removing 0.5 microliter of the reaction mixture and adding it to 4.5 microliter of a MALDI matrix solution, such as caffeic acid (approximately 12 mg/mL) and 70% acetonitrile/water. The reaction mixture is then subjected to MALDI mass spectrometry. The MALDI surface is prepared by the method of Xiang and Beavis (Xiang and Beavis (1994) Rapid. Commun. Mass. Spectrom. 8, 204). A two-fold lower access of basic peptide (Arg/Gly)15 is premixed with matrix before being added to the oligosaccharide solution. A 1 microliter aliquot of sample/matrix mixture containing 1-3 picomoles of oligosaccharide is deposited on the surface. After crystallization occurs (typically within 60 seconds), excess liquid is rinsed off with water. MALDI mass spectrometry spectra is then acquired in the linear mode by using a PerSeptive Biosystems (Framingham, MA) Voyager Elite reflectron time-of flight instrument fitted with a 337 nanometer nitrogen laser. Delayed extraction is used to increase resolution (22 kV, grid at 93%, guidewire at 0.15%, pulse delay 150 ns, low mass gate at 1,000, 128 shots averaged). Mass spectra are calibrated externally by using the signals for proteinated (Arg/Gly)15 and its complex with the oligosaccharide.
Capillary electrophoresis may then be performed on a Hewlett-Packard3D CE unit by using uncoated fused silica capillaries (internal diameter 75 micrometers, outer diameter 363 micrometers, ldec 72.1 cm, and It°t 85 cm). Analytes are monitored by using UV detection at 233 nm and an extended light path cell (Hewlett-Packard). The electrolyte is a solution of 10 microliter dextran sulfate and 50 millimolar Tris/phosphoric acid (pH 2.5). Dextran sulfate is used to suppress nonspeciftc interactions of the glycosaminoglycan oligosaccharides with a silica wall.
Separations are carried out at 30 kV with the anode at the detector side (reversed polarity). A
mixture of a I/5-naphtalenedisulfonic acid and 2-naphtalenesulfonic acid (10 micromolar each) is used as an internal standard.
Additionally, the coupling of CE and MALDI-MS with enzymes and a bioinformatics-based, property-encoded nomenclature (PEI have led to a sequencing strategy (PEN-MALDI) described in (Venkataraman, G., Shriver, Z., Raman, R., and Sasisekharan, R. (1999) Science 286, 537-42).
Other methods for assessing the product profile may also be utilized. For instance, other methods include methods which rely on parameters such as viscosity to (Jandik, I~.A., Gu, K. and Linhardt, R.J., (1994), Glycobiology, 4:284-296) or total UV
absorbance (Ernst, S. et al., (1996), Biochern. .1., 315:589-597) or mass spectrometry or capillary electrophoresis alone.
The enzymes and compositions provided herein can also be used in methods for analyzing the purity of a sample of polysaccharides, methods for determining the presence of a polysaccharide in a sample, methods for determining the composition of a polysaccharide in a sample and the like. As used herein a "method for determining the composition of a polysaccharide in a sample" is intended to encompass methods whereby one or more of the polysaccharides in the sample are identified. In some instances the method is one in which all of the polysaccharides in the sample are identified. In other instances the method encompasses the quantity as well as the identity of one or more of the polysaccharides in the sample.
As used herein, a "polysaccharide" is a polymer composed of monosaccharides linked to one another. In many polysaccharides the basic building block of the polysaccharide is actually a disaccharide unit, which can be repeating or non-repeating.
Thus, a unit when used with respect to a polysaccharide refers to a basic building block of a polysaccharide and can include a monomeric building block (monosaccharide) or a dimeric building block (disaccharide). The term polysaccharide is also intended to embrace an oligosaccharide. Polysaccharides include but are not limited to glycosaminoglycans such as chondroitin, chondroitin sulfate, dermatan sulfate, 3o chondroitin-6 sulfate, chondroitin-4 sulfate, chondroitin D, chondroitin E, heparin, heparin-like glycosaminoglycans (HLGAGs), heparan sulfate, hyaluronic acid, keratan -sz-sulfate, and derivatives or analogs thereof, chitin in derivatives and analogs thereof. In some embodiments the GAGS are in the form of chains associated with core protein, such as proteoglycans.
In addition to polysaccharides from natural sources, the polysaccharides of the invention also include molecules that are biotechnologically prepared, chemically modified and synthetic. The term "biotechnological prepared" encompasses polysaccharides that are prepared from natural sources of polysaccharides which have been chemically modified. This is described for example in Razi et al., Bioche. J. 1995 Jul 15;309 (Pt 2): 465-72 and in Yates et al., Carbohydrate Res (1996) Nov 20;294:15 27, and is known to those of skill in the art. Synthetic polysaccharides are also well known to those of skill in the art and is described in Petitou, M. et al., Bioorg Med Chem Lett. (1999) Apr 19;9(8):1161-6.
As used herein a "sample" of polysaccharides is meant to include any sample which has one or more polysaccharides contained therein.
One of ordinary skill in the art, in light of the present disclosure, is enabled to produce preparations of polysaccharide, e.g. glycosaminoglycan (GAG) or galactosaminoglycan (GalAG) fragment compositions utilizing the chondroitinase ABC I
molecules alone or in conjunction with other enzymes as well as with the compositions provided herein. GAG or GaIAG fragments have many therapeutic utilities. The GAG
or GaIAG fragment preparations are prepared from polysaccharide sources. A
"polysaccharide source" as used herein refers to glycosaminoglycan composition which can be manipulated to produce GAG or GalAG fragments. As described above, GAG
or GaIAG include but are not limited to isolated chondroitin sulfate, dennatan sulfate as well as chemically modified, biotechnology pxepared and synthetic versions of such polysaccharides. Thus GAG or GalAG can be isolated from natural sources, prepared by direct synthesis.
The teens "polysaccharide fragment" and "GAG or GaIAG fragment" as used herein refers to the resultant products) from the activity, respectively, of a polysaccharide-degrading or GAG or GalAG degrading enzyme on a polysaccharide or 3o GAG or GalAG. The GAG or GaIAG fragments can include portions of the original GAG or GalAG (prior to the action of the enzyme) or a modified version of the original GAG or GaIAG (e.g., desulfated version). The GAG or GalAG fragment, in some embodiments, has therapeutic activity.
For instance, the GE~.G or GalAG fragment can promote nerve regeneration, promote stroke recovery or prevent the proliferation and/or metastasis of a tumor cell.
The GAG or GaIAG fragment can also be used to inhibit or treat microbial infection, to treat a coagulation disorder, to stabilize the extracellular matrix, to promote cell proliferation or to promote organogenesis. The GAG or GaIAG fragment can also treat epithelial diseases, such as cystic fibrosis or viral, bacterial or pathogen infection. The use of the GAG or GaIAG fragments for other desired therapeutic activities are described to below. Such compounds rnay be generated using chondroitinase ABC I to produce therapeutic fragments or they may be synthesized de rzovo based on information derived from the use of chondroitinase ABC I. GAG or GalAG fragments can be tested for therapeutic activity using any of the assays described herein or known in the art. Thus the therapeutic GAG or GaIAG fragment may be a synthetic GAG or GalAG fragment generated based on the sequence of the GAG or GaIAG fragment identified when a polysaccharide source is contacted with chondroitinase ABC I, or having minor variations which do not interfere with the activity of the compound.
Alternatively the therapeutic GAG or GalAG fragment may be an isolated GAG or GaIAG fragment produced when the polysaccharide source is contacted with chondroitinase ABC
I.
2o Thus, the methods of the invention enable one of skill in the art to prepare or identify an appropriate composition of GAG or GaIAG fragments, depending on the subject and the disorder being treated. These compositions of GAG or GaIAG
fragments may be used alone or in combination with other GAG or GalAG fragments, chondroitinase ABC I and/or other enzymes. Likewise chondroitinase ABC I may also be used to produce GAG or GalAG fragments irz vivo alone or in conjunction with other enzymes.
The chondroitinase ABC I molecules andlor GAG or GalAG fragments produced using the chondroitinase ABC I or composition described herein can be used for the treatment of any type of condition or circumstance in which chondroitinase ABC
I
3o therapy and/or GAG or GaIAG fragment therapy has been identified as a useful therapy, e.g., promoting nerve regeneration, such as after spinal cord injury, promoting stroke recovery, preventing coagulation, treating a coagulation disorder, inhibiting angiogenesis, inhibiting proliferation, inhibiting cancer cell growth and metastasis, preventing angiogenesis, preventing neovascularization, treating neurodegenerative disorders, treating psoriasis, inhibiting or treating microbial infection, to stabilize the extracellular matrix, to spur cell proliferation, to promote organogenesis, etc. The chondroitinase ABC I and/or GAG or GaIAG fragments can alsa be used for mediating cell signaling. Thus, the invention is useful in a variety of izz vitz-o, izz vivo and ex vivo methods in which therapies are useful. Chondroitinase ABC I is also useful in the treatment of ostoearthritis and maternal malarial infection. The GAG or GalAG
to fragment compositions may also be used in irz vitro assays, such as a quality control sample.
The disorders provided herein are known in the art and/or are described in, for instance, Har>~isorz's PrirrcipZes of Izzternal Medicine (McGraw Hill, Inc., New York), which is incorporated by reference.
i5 In one embodiment the preparations of the invention are used for promoting nerve regeneration. An effective amount for promoting nerve regeneration of the GAG
or GaIAG fragment preparation and/or chondroitinase ABC I or other composition provided herein is administered to a subject in need of treatment thereof. The subject in need of treatment thereof includes subjects that suffer from nerve disorders, such as 2o diseases associated with neurodegeneration and injuries that result in nerve damage, in which nerve regeneration is desirable. In some embodiments the subject suffers from a central nervous system injury, such as a spinal cord injury, a brain injury, has suffered a stroke, a neurodegenerative disease, multiple sclerosis or any other disease or condition that causes or results in a loss of neurons or neuronal connections. "Central nervous 25 system" as used herein is intended to include the brain, the spinal cord and neurons whose cell bodies lie within or have a primary synapse in the brain or spinal cord.
Examples of such neurons include neurons of the cranial nerves (damage to which can cause, for example, Bell's palsy) and motor neurons that innervate the musculature and whose cell bodies are in the ventral horn of the spinal cord. "Spinal cord injury" as used 3o herein includes, but is not limited to, injury cause by assault, accident, tumor, intervertebral disc or bone abnormality, or surgery. The methods and compositions provided herein, however, are also directed to treatment of central nervous system damage other than spinal cord injury. Central nervous system damage includes, for example, stroke, brain injury, multiple sclerosis and neurodegenerative disease, such as Alzheimer's.
The terms "treat" and "treating" as used herein refer to partially or completely promoting nerve cell regeneration and/or motility or migration of a nerve cell. The terms also refer to partially or completely restoring motor/physical function. The term also encompasses axon regeneration. Axon regeneration, for example, includes sensory and motor axon regeneration.
The nerve cells may be treated in vivo, in vitro, or ex vivo. Thus, the cells may be in an intact subject or isolated from a subject or alternatively may be an irZ
vitro cell line.
Thus the invention contemplates the treatment of subjects having or at risk of developing neurodegenerative disease or suffering an injury to nerve cells.
Neuronal cells are predominantly categorized based on their Iocal/regional synaptic connections (e.g., local circuit interneurons vs. longrange projection neurons) and receptor sets, and associated second messenger systems. Neuronal cells include both central nervous system (CNS) neurons and peripheral nervous system (PNS) neurons. There are many different neuronal cell types. Examples include, but are not limited to, sensory and sympathetic neurons, cholinergic neurons, dorsal root ganglion neurons, proprioceptive 2o neurons (in the trigeminal mesencephalic nucleus), ciliary ganglion neurons (in the parasympathetic nervous system), etc. A person of ordinary skill in the art will be able to easily identify neuronal cells and distinguish them from non-neuronal cells such as glial cells, typically utilizing cell-morphological characteristics, expression of cell-speci~c markers, secretion of certain molecules, etc.
"Neurodegenerative disorder" is defined herein as a disorder in which progressive loss of neurons occurs either in the peripheral nervous system or in the central nervous system. Examples of neurodegenerative disorders include: (i) chronic neurodegenerative diseases such as familial and sporadic amyotrophic lateral sclerosis (FALS and ALS, respectively), familial and sporadic Parkinson's disease, Huntington's disease, familial and sporadic Alzheimer's disease, multiple sclerosis, olivopontocerebellar atrophy, multiple system atrophy, progressive supranuclear palsy, diffuse Lewy body disease, corticodentatonigral degeneration, progressive familial myoclonic epilepsy, strionigral degeneration, torsion dystonia, familial tremor, Down's Syndrome, Gilles de la Tourette syndrome, HaIIervorden-Spatz disease, diabetic peripheral neuropathy, dementia pugilistica, AIDS dementia, age related dementia, age associated memory impairment, and amyloidosis-related neurodegenerative diseases such as those caused by the prion protein (PrP) which is associated with transmissible spongiform encephalopathy (Greutzfeldt-Jakob disease, Gerstmann-Straussler-Scheinker syndrome, scrapic, and kuru), and those caused by excess cystatin C
accumulation (hereditary cystatin C angiopathy); and (ii) acute yzeurodegefterative disorders such as to traumatic brain injury (e.g., surgery-related brain injury), cerebral edema, peripheral nerve damage, spinal cord injury, Leigh's disease, Guillain-Barre syndrome, lysosomal storage disorders such as lipofuscinosis, Alpex's disease, vertigo as result of CNS
degeneration; pathologies arising with chronic alcohol or drug abuse including, for example, the degeneration of neurons in locus coeruleus and cerebellum;
pathologies arising with aging including degeneration of cerebellar neurons and cortical neurons leading to cognitive and motor impairments; and pathologies arising with chronic amphetamine abuse including degeneration of basal ganglia neurons leading to motor impairments; pathological changes resulting from focal trauma such as stroke, focal ischemia, vascular insufficiency, hypoxic-ischemic encephalopathy, hyperglycemia, zo hypoglycemia or direct trauma; pathologies arising as a negative side-effect of therapeutic drugs and treatments (e.g., degeneration of cingulate and entorhinal cortex neurons in response to anticonvulsant doses of antagonists of the NMDA class of glutamate receptor). and Wernicke-I~orsakoff s related dementia.
Neurodegenerative diseases affecting sensory neurons include Friedreich's ataxia, diabetes, peripheral neuropathy, and retinal neuronal degeneration. Neurodegenerative diseases of limbic and cortical systems include cerebral amyloidosis, Pick's atrophy, and Retts syndrome.
The foregoing examples are not meant to be comprehensive but serve merely as an illustration of the term "neurodegenerative disorder"
The compositions provided herein can be combined with other treatments used to 3o promote nerve regeneration or treat neurodegenerative disease.

For example, antiparkinsonian agents include but are not limited to Benztropine Mesylate; Biperiden; Biperiden Hydrochloride; Biperiden Lactate; Carmantadine;
Ciladopa Hydrochloride; Dopamantine; Ethopropazine Hydrochloride; Lazabemide;
Levodopa; Lometraline Hydrochloride; Mofegiline Hydrochloride; Naxagolide Hydrochloride; Pareptide Sulfate; Procyclidine Hydrochloride; Quinelorane Hydrochloride; Ropinirole Hydrochloride; Selegiline Hydrochloride; Tolcapone;
Trihexyphenidyl Hydrochloride. Drugs for the treatment of amyotrophic lateral sclerosis include but are not limited to Riluzole. Drugs for the treatment of Paget's disease include but are not limited to Tiludronate Disodium.
l0 Therefore, compositions and methods are provided for treating spinal cord injury.
Spinal cord injury currently affects 3-5 out of every 100,000 Americans.
11,000 new cases occur each year in the United States, approximately ~0% of which are men. Most of the people who suffer from spinal cord injury are completely or partially paralyzed, and such paralysis usually lasts throughout the injured individual's lifetime and is generally though to be incurable. The consequences to the injured, their friends and family can be devastating, and, therefore, any treatment would have a profound impact on the quality of life of injured patients.
Administration can be by any conventional route, including any route capable of delivering the chondroitinase ABC I enzymes and/or GAG or GalAG fragments provided herein across the blood brain barner. The route of administration can be by direct administration to the central nervous system, e.g., by infusion via cannula or injection.
The administration can be directly to the site of injury, neighboring tissues or into the cerebrospinal fluid. Administration can be effected by any of the other ways that are known in the art. In some embodiments the method of administration can include targeting to chondroitinase ABC I enzyme and/or GAG or GalAG fragment to the site in need of treatment. Therefore, in some embodiments the chondroitinase ABC I
enzyme and/or GAG fragment is targeted to the site through the use of a targeting molecule.
Targeting molecules for delivery to the central nervous system include, for example, tetanus neurotoxin fragments (e.g., H~).

Therefore, chondroitinase ABC I enzymes and/or GAG or GalAG fragments provided can be conjugated to a targeting molecule and compositions thereof are also provided.
The chondroitinase ABC T molecules and GAG or GaIAG fragment preparations are useful for treating or preventing disorders associated with coagulation. A
"disease associated with coagulation" as used herein refers to a condition characterized by inflammation resulting from an interruption in the blood supply to a tissue, which may occur due to a blockage of the blood vessel responsible for supplying blood to the tissue such as is seen for myocardial, cerebral infarction, or peripheral vascular disease, or as a to result of embolism formation associated with conditions such as a°al fibrillation or deep venous thrombosis. A cerebral ischemic attack or cerebral ischernia is a form of ischemic condition in which the blood supply to the brain is blocked. This interruption in the blood supply to the brain may result from a variety of causes, including an intrinsic blockage or occlusion of the blood vessel itself, a remotely originated source of occlusion, decreased perfusion pressure or increased blood viscosity resulting in inadequate cerebral blood flow, or a ruptured blood vessel in the subarachnoid space or intracerebral tissue.
The chondroitinase ABC T or the GAG ox GaIAG fragments generated therewith may be used alone or in combination with a therapeutic agent for treating a disease 2o associated with coagulation. Examples of therapeutics useful in the treatment of diseases associated with coagulation include anticoagulation agents, antiplatelet agents, and thrombolytic agents.
Anticoagulants include, but are not limited to, heparin, warfarin, coumadin, dicumarol, phenprocoumon, acenocoumarol, ethyl biscoumacetate, and indandione derivatives.
Antiplatelet agents include, but are not limited to, aspirin, thienopyridine derivatives such as ticlopodine and clopidogrel, dipyridamole and sulfinpyrazone, as well as RGD mimetics and also antithrombin agents such as, but not limited to, hirudin.
Thrombolytic agents include, but are not limited to, plasminogen, a2-antiplasmin, 3o streptokinase, antistreplase, tissue plasminogen activator (tPA), and urokinase. ' In one embodiment the preparations of the invention are used for inhibiting angiogenesis. An effective amount for inhibiting angiogenesis of the GAG or GalAG
fragment preparation or chondroitinase ABC I is administered to a subject in need of treatment thereof. Angiogenesis as used herein is the inappropriate formation of new blood vessels. "Angiogenesis" often occurs in tumors when endothelial cells secrete a group of growth factors that are mitogenic for endothelium causing the elongation and proliferation of endothelial cells which results in a generation of new blood vessels. The inhibition of angiogenesis can cause tumor regression in animal models, suggesting a use as a therapeutic anticancer agent. An effective amount for inhibiting angiogenes~s is an i0 amount of GAG or GalAG fragment preparation and/or a chondroitinase ABC I
v~rhich is sufficient to diminish the number of blood vessels growing into a tumor. This amount can be assessed in an animal model of tumors and angiogenesis, many of which are known in the art.
The compositions of the invention are useful for treating and preventing cancer cell proliferation and metastasis. Thus, according to another aspect of the invention, there is provided methods for treating subjects having or at risk of having cancer. The terms "treat" and "treating" tumor cell proliferation as used herein refer to inhibiting completely or partially the proliferation or metastasis of a cancer or tumor cell, as well as inhibiting any increase in the proliferation or metastasis of a cancer or tumor cell.
A "subject having a cancer" is a subject that has detectable cancerous cells.
The cancer may be a malignant or non-malignant cancer. Cancers or tumors include but are not limited to biliary tract cancer; brain cancer; breast cancer; cervical cancer;
choriocarcinoma; colon cancer; endometrial cancer; esophageal cancer; gastric cancer;
intraepithelial neoplasms; lymphomas; liver cancer; lung cancer (e.g. small cell and non-small cell); melanoma; neuroblastomas; oral cancer; ovarian cancer;
pancreas cancer; prostate cancer; rectal cancer; sarcomas; skin cancer; testicular cancer; thyroid cancer; and renal cancer, as well as other carcinomas and sarcomas. Cancers also include cancer of the blood and larynx.
A "subject at risk of having a cancer" as used herein is a subject who has a high 3o probability of developing cancer. These subjects include, for instance, subjects having a genetic abnormality, the presence of which has been demonstrated to have a correlative relation to a higher likelihood of developing a cancer and subjects exposed to cancer causing agents such as tobacco, asbestos, or other chemical toxins, or a subject who has previously been treated for cancer and is in apparent remission. When a subject at risk of developing a cancer is treated with a chondroitinase ABC I or degradation product thereof the subject may be able to kill the cancer cells as they develop.
When administered to a patient undergoing cancer treatment, the chondroitinase ABC I and/or GAG or GaIAG fragment may be administered in cocktails containing other anti-cancer agents. The compounds may also be administered in cocktails containing agents that treat the side-effects of radiation therapy, such as anti-emetics, radiation protectants, etc.
Anti-cancer agents also can include cytotoxic agents and agents that act on tumor neovasculature. Cytotoxic agents include cytotoxic radionuclides, chemical toxins and protein toxins. The cytotoxic radionuclide or radiotherapeutic isotope preferably is an alpha-emitting isotope such aS 225AC, 211At, 212$1, 213Bi~ 212Pb' 224Ra Or 223Rd.
Alternatively, the cytotoxic radionuclide may a beta-emitting isotope such as ls6Rh, lss~~ l~~Lu~ ~o~,~ 131h 67Cu~ s4Cu~ ls3Sm or l6sHo. Further, the cytotoxic radionuclide may emit Auger and low energy electrons and include the isotopes 1251, lz3l or 7~Br.
Suitable chemical toxins or chemotherapeutic agents include members of the enediyne family of molecules, such as calicheamicin and esperamicin. Chemical toxins 2o can also be taken from the group consisting of methotrexate, doxorubicin, melphalan, chlorambucil, ARA-C, vindesine, mitomycin C, cis-platinum, etoposide, bleomycin and

5-fluorouracil. Toxins also include poisonous lectins, plant toxins such as ricin, abrin, modeccin, botulina and diphtheria toxins. Of course, combinations of the various toxins are also provided thereby accommodating variable cytotoxicity. Other chemotherapeutic agents are known to those skilled in the art.
Agents that act on the tumor vasculature can include tubulin-binding agents such as combrestatin A4 (Griggs et al., Lancet Oncol. 2:82, 2001), angiostatin and endostatin (reviewed in Rosen, Oncologist 5:20, 2000, incorporated by reference herein), interferon inducible protein 10 (U.S. Patent No. 5,994,292), and the like. Anticancer agents also 3o include immunomodulators such as a-interferon, 'y-interferon, and tumor necrosis factor alpha (TNFoc).

The invention also encompasses screening assays for identifying therapeutic GAG or GalAG fragments for the treatment of any of the conditions/disorders provided herein, such as the treatment of a tumor, for preve=rating metastasis or other treatment endpoints. The assays may be accomplished, for instance, by treating a tumor or isolated tumor cells with chondroitinase ABC I alone or in soiree combination with other native or modified GAG or GaIAG degrading enzymes, such as heparinases, and isolating the resultant GAG or GaIAG fragments. The isolated GAG or GaIAG fragments may then be tested for therapeutic activity in the prevention of tumor cell proliferation and metastasis. Thus the invention encompasses individualized therapies, in which a tumor to or portion of a tumor is isolated from a subject and used to prepare the therapeutic GAG
or GaIAG fragments. These therapeutic fragments can be re-administered to the subject to protect the subject from further tumor cell proliferation or metastasis or from the initiation of metastasis if the tumor is not yet metastatic. Alternatively the fragments can be used in a different subject having the same type o~ tumor or a different type of tumor.
Effective amounts of the chondroitinase ABC I and/or GAG or GalAG
fragments, or compositions that contain them, o~ the invention are administered to subjects in need of such treatment. Effective amounts are those amounts which will result in a desired improvement in the condition or symptoms of the condition, e.g., for cancer this is a reduction in cellular proliferation or metastasis, while for 2o neurodegenerative disease or damage this is the regeneration of nerve cells, the prolonged survival of nerve cells, the migration of nerve cells or the restoration of nerve function. The amount effective can be the amount of a single agent that produces a desired result or can be the amount of two or more agents in combination. Such amounts can be determined with no more than routine experimentation.
It is believed that doses ranging froze 1 nanogram/kilogram to 100 milligrams/kilogram, depending upon the mode of administration, will be effective. The absolute amount will depend upon a variety of factors (including whether the administration is in conjunction with other methods of treatment, the number of doses and individual patient parameters including age, physical condition, size and weight) and 3o can be determined with routine experimentatior~. It is preferred generally that a maximum dose be used, that is, the highest safe dose according to sound medical judgment. The mode of administration may be anymedically acceptable mode including oral, subcutaneous, intravenous, etc.
In some aspects of the invention the effective amount of chondroitinase ABC I
and/or GAG or GalAG fragment is that amount effective to prevent invasion of a tumor cell across a barrier. The invasion and metastasis of cancer is a complex process which involves changes in cell adhesion properties which allow a transformed cell to invade and migrate through the extracellular matrix (ECM) and acquire anchorage-independent growth properties. Liotta, L. A., et al., Cell 64:327-336 (I99I). Some of these changes occur at focal adhesions, which are cell/ECM contact points containing membrane-1o associated, cytoskeletal, and intracellular signaling molecules. Metastatic disease occurs when the disseminated foci of tumor cells seed a tissue which supports their growth and propagation, and this secondary spread of tumor cells is responsible for the morbidity and mortality associated with the majority of cancers. Thus the term "metastasis" as used herein refers to the invasion and migration of tumor cells away from the primary tumor site.
The barrier for the tumor cells may be an artificial barrier in vitro or a natural barrier ira vivo. In vitro barriers include but are not limited to extracellular matrix coated membranes, such as Matrigel. Thus the chondroitinase ABC I compositions or degradation products thereof can be tested for their ability to inhibit tumor cell invasion 2o in a Matrigcl invasion assay system as described in detail by Parish, C.R., et al., "A
Basement-Membrane Permeability Assay which Correlates with the Metastatic Potential of Tumour Cells," Int. J. Cancer (1992) 52:378-383. Matrigel is a reconstituted basement membrane containing type IV collagen, laminin, heparan sulfate proteoglycans such as perlecan, which bind to and localize bFGF, vitronectin as well as transforming growth factor- (3 (TGF-(3), urokinase-type plasminogen activator (uPA), tissue plasminogen activator (tPA), and the serpin known as plasminogen activator inhibitor type 1 (PAI-1). Other in vitro and in vivo assays for metastasis have been described in the prior art, see, e.g., US Patent No. 5,935,850, issued on August 10, 1999, which is incorporated by reference. An in vivo barrier refers to a cellular barner present in the body of a subject.

The chondroitinase ABC I and/or GAG or GaIAG fragments may also be linked to a targeting molecule. A targeting molecule is any molecule or compound which is specific for a particular cell or tissue and which can be used to direct the cho~ndroitinase ABC I and/or GAG or GaIAG to the cell or tissue. Preferably the targeting molecule is a molecule which specifically interacts with a cancer cell or a tumor. For ir~stance, the targeting molecule may be a protein or other type of molecule that recognizes and specifically interacts with a tumor antigen_ Tumox-antigens include Melan-A/MART-I, Dipeptidyl peptidase I~ (DPPIV), adenosine deaminase-binding protein (ADAbp), cyclophilin b, Colorectal associated l0 antigen (CRC)--COI7-lA/GA733, Carcinoembryonic Antigen (CEA) and its immunogenic epitopes CAP-1 and CAP-2, etv6, amll, Prostate Specific Ant-~gen (PSA) and its immunogenic epitopes PSA-1, PSA-2, and PSA-3, prostate-specific membrane antigen (PSMA), T-cell receptor/CD3-zeta chain, MAGE-family of tumor antigens (e.g., MAGE-Al, MAGE-A2, MAGE-A3, MAGE-A4, MACE-A5, MAGE-A6, :IMAGE-A7, MAGE-A8, MAGE-A9, MAGE-A10, MAGE-Al l, MAGE-A12, MACE-Xp2 (MAGE-B2), MACE-Xp3 (MACE-B3), MAGE-Xp4 IMAGE-B4), MAGE-CI, IMAGE-C2, MACE-C3, MAGE-C4, MAGE-CS), GAGE-family of tumor antigens (e.g_, GAGE-l, GAGE-2, GAGE-3, GAGE-4, GAGE-5, GAGE-6, GAGE-7, GAGE-8, GAGE-9), BAGS, RAGE, LAGE-1, NAG, GnT-V, MLTM-l, CDI~4, tyrosinase, p53, IVJ~UC family, HER2/neu, p2lras, RCAS1, a.-fetoprotein, E-cadherin, a-catenin, j3-cate=nin and y-catenin, pl20ctn, gpI00P'T'e111~~ PEE, NY-ESO-I, brain glycogen phosphorylase, SSX-l, SSX-2 (HOM-MEL-40), SSX-l, SSX-4, SSX-5, SCP-1, CT'-7, cdc27, adenomatous polyposis coli protein (APC), fodrin, P1A, Connexin 37, Ig-id3otype, pIS, gp75, GM2 and GD2 gangliosides, viral products such as human papilloma virus proteins, Smad family of tumor antigens, lmp-l, EBV-encoded nuclear antigen (EBNA)-I, and c-erbB-2.
The preparations of the present invention may also be used to inhibit or treat infections, such as viral, bacterial, pathogenic or microbial infections. For Lnstance, the preparations provided can be used to inhibit binding to CS/DS proteoglycarLS
that act as cell adhesion molecules, particularly during infection (e.g. malarial infectiron). It has been found that in pregnant women infected with Plasrnodium falciparum infected red blood cells (IRBCs) accumulate in the placenta. 'The accumulation of IRBCs is believed to be due to the adhesion of IRBC membrane proteins to molecules found in the intervillous space in the placenta such as chondroitin 4-sulfate (Achur et.
al., 2000, The Journal of Biological Chemistry, Vol. 275, No. 51 and Alkhalil, et. aL, 2000, The Journal of Biological Chemistry, Vol. 275, No. 51). One aspect of the present invention, therefore, is a method for inhibiting maternal malarial infection. An effective amount for treating malarial infection is that amount that leads to a decrease in the number of infected red blood cells in the placenta sufficient that eliminate or decrease the undesirable effects of malarial infection during pregnancy. These effects include: low birth weight, still birth, abortion, premature delivery and maternal morbidity and mortality (Achur et. al., 2000, The Journal of Biological Chemistry, Vol. 275, No. 51).
The preparations provided herein can be used for the treatment of osteoarthritis or psoriasis. Treatment of osteoarthritis refers to any reduction of the subject's symptoms associated with osteoarthritis or controlling the progression of the disease.
Generally treatment of osteoarthritis includes reducing pain and/or improving joint movement.
Treatment of psoriasis includes the reduction of symptoms of the disease, such as reducing the shedding of skin, or controlling the progression of the disease.
Treatment includes, therefore, methods for reducing inflammation associated with psoriasis. As used herein "controlling the progression of the disease" refers to any reduction in the rate of the progression of the disease. The term also includes halting disease progression.
The methods and compositions provided herein can also include other treatments used in osteoarthritis or psoriatic subjects. Other osteoarthritic treatments include NSAIDS and corticosteroids. Other psoriatic treatments include steroids, such as cortisone; scalp treatment with coal tar or cortisone (at times in combination with salicylic and lactic acid); anthralin; vitamin D (synthetic vitamin D analogue (calcipotriene)); retinoids (prescription vitamin A-related gels, creams (tazarotene), and oral medications (isotrentinoin, acitretin)); coal tar; Goeckerman Treatment (coal tar dressings and ultraviolet light); light therapy (Ultraviolet light B (UVB));
psoralen and UVA (PUVA); methotrexate; cyclosporine; alefacept; etancercept; infliximab;
3o adalimumab; and efalizumab.

The methods provided also include methods of using the chondroitinase ABC I
enzymes, polysaccharide fragments and compositions provided herein to modulate the extracellular matrix and/or to target specific cell-surface architecture for the diagnosis and treatment of disease.
The methods provided also include methods of promoting cellular proliferation or organogenesis with the preparations provided.
The chondroitinase ABC I is, in some embodiments, immobilized on a support.
The chondroitinase ABC I may be immobilized to any type of support but if the support is to be used in vivo or ex vivo it is desired that the support is sterile and biocompatible.
1o A biocompatible support is one which would not cause an immune or other type of damaging reaction when used in a subject. The chondroitinase ABC I may be immobilized by any method known in the art. Many methods are known for immobilizing proteins to supports. A "solid support" as used herein refers to any solid material to which a polypeptide can be immobilized.
Solid supports, for example, include but are not limited to membranes, e.g., natural and modified celluloses such as nitrocellulose or nylon, Sepharose, Agarose, glass, polystyrene, polypropylene, polyethylene, dextran, amylases, polyacrylamides, polyvinylidene difluoride, other agaroses, and magnetite, including magnetic beads. The Garner can be totally insoluble or partially soluble and may have any possible structural 2o configuration. Thus, the support may be spherical, as in a bead, or cylindrical, as in the inside surface of a test tube or microplate well, or the external surface of a rod.
Alternatively, the surface may be flat such as a sheet, test strip, bottom surface of a microplate well, etc.
The chondroitinase ABC I may also be used to remove active GAGs or GaIAGs from a GAG or GalAG containing fluid. A GAG or GalAG containing fluid is contacted with the chondroitinase ABC I of the invention to degrade the GAG or GaIAG.
The method is particularly useful for the ex vivo removal of GAGS or GaIAGs from blood. In one embodiment the chondroitinase ABC I may be immobilized on a solid support as is conventional in the art. The solid support containing the immobilized chondroitinase 3o ABC I may be used in extracorporeal medical devices (e.g. hemodialyzer, pump-oxygenator) to prevent the blood in the device from clotting. The support membrane containing immobilized chondroitinase ABC I is positioned at the end of the device to neutralize the GAG or GaIAG before the blood is returned to the body.
Compositions comprising the chondroitinase ABC I enzymes are also provided.
Such compositions can be used in any of the methods provided herein.
In general, when administered for therapeutic purposes, the formulations of the invention are applied in pharmaceutically acceptable solutions. Such preparations may routinely contain pharmaceutically acceptable concentrations of salt, buffering agents, preservatives, compatible carriers, adjuvants, and optionally other therapeutic ingredients.
l0 The compositions of the invention may be administered per se (neat) or in the form of a pharmaceutically acceptable salt. When used in medicine the salts should be pharmaceutically acceptable, but non-pharmaceutically acceptable salts may conveniently be used to prepare pharmaceutically acceptable salts thereof and are not excluded from the scope of the invention. Such pharmacologically and pharmaceutically acceptable salts include, but are not limited to, those prepared from the following acids:
hydrochloric, hydrobromic, sulphuric, nitric, phosphoric, malefic, acetic, salicylic, p-toluene sulphonic, tartaric, citric, methane sulphonic, formic, malonic, succinic, naphthalene-2-sulphonic, and benzene sulphonic. Also, pharmaceutically acceptable salts can be prepared as alkaline metal or alkaline earth salts, such as sodium, potassium or calcium salts of the carboxylic acid group.
Suitable buffering agents include: acetic acid and a salt (1-2% W/V); citric acid and a salt (1-3% W/V); boric acid and a salt (0.5-2.5% W/V); and phosphoric acid and a salt (0.8-2% W/V). Suitable preservatives include benzalkonium chloride (0.003-0.03%
W/V); chlorobutanol (0.3-0.9% W/V~; parabens (0.01-0.25% W/V) and thimerosal (0.004-0.02% W/V~.
The present invention provides pharmaceutical compositions, for medical use, which comprise chondroitinase ABC I and/or GAG or GalAG fragments together with one or more pharmaceutically acceptable Garners and optionally other therapeutic ingredients. The term "pharmaceutically-acceptable carrier" as used herein, and 3o described more fully below, means one or more compatible solid or liquid filler, dilutants or encapsulating substances which are suitable for administration to a human or other animal. In the present invention, the term "carner" denotes an organic or inorganic ingredient, natural or synthetic, with which the active ingredient is combined to facilitate the application. The components of the pharmaceutical compositions also are capable of being commingled with the chondroitinase ABC I and/or GAG or GalAG fragments, and with each other, in a manner such that there is no interaction which would substantially impair the desired pharmaceutical efficiency.
The enzymes, fragments and compositions provided herein can be combined with a physiologically acceptable Garner. The term "physiologically-acceptable"
refers to a non-toxic material that is compatible with the biological systems such of a tissue or l0 organism. The physiologically acceptable carrier must be sterile for i~
vivo administration. The characteristics of the Garner will depend on the route of administration.
A variety of administration routes are available. 'The particular mode selected will depend, of course, upon the particular active agent selected, the particular condition being treated and the dosage required for therapeutic efficacy. The methods of this invention, generally speaking, may be practiced using any mode of administration that is medically acceptable, meaning any mode that produces effective levels of an immune response without causing clinically unacceptable adverse effects. A preferred mode of administration is a parenteral route. The term "parenteral" includes subcutaneous 2o injections, intravenous, intramuscular, intraperitoneal, intrasternal injection or infusion techniques. Other modes of administration include oral, mucosal, rectal, vaginal, sublingual, intranasal, intratracheal, inhalation, ocular, transdermal, etc.
For oral administration, the compounds can be formulated readily by combining the active compounds) with pharmaceutically acceptable carriers well known in the art.
Such carriers enable the compounds of the invention to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurnes, suspensions and the like, for oral ingestion by a subject to be treated. Pharmaceutical preparations for oral use can be obtained as solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or 3o dragee cores. Suitable excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol; cellulose preparations such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, andlor polyvinylpyrrolidone (PVP). If desired, disintegrating agents may be added, such as the cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof such as sodium alginate. Optionally the oral formulations may also be formulated in saline or buffers for neutralizing internal acid conditions or may be administered without any carriers.
Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer to solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.
Pharmaceutical preparations which can be used orally include push-ft capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as i5 glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with filler such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. In addition, stabilizers may be added.
2o Microspheres formulated for oral administration may also be used. Such microspheres have been well defined in the art. All formulations for oral administration should be in dosages suitable for such administration.
For buccal administration, the compositions may take the form of tablets or lozenges formulated in conventional manner.
25 For administration by inhalation, the compounds for use according to the present invention may be conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit may be 3o determined by providing a valve to deliver a metered amount. Capsules and cartridges of e.g. gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.
The compounds, when it is desirable to deliver them systemically, may be formulated for parenteral administration by injection, e.g., by bolus injection or continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in mufti-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents.
1o Pharmaceutical formulations for parenteral administration include aqueous solutions of the active compounds in water-soluble form. Additionally, suspensions of the active compounds may be prepared as appropriate oily injection suspensions.
Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters, such as ethyl oleate or triglycerides, or Iiposomes.
Aqueous injection suspensions may contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Optionally, the suspension may also contain suitable stabilizers or agents which increase the solubility of the compounds to allow for the preparation of highly concentrated solutions.
Alternatively, the active compounds may be in powder form for constitution with 2o a suitable vehicle, e.g., sterile pyrogen-free water, before use.
The compounds may also be formulated in rectal or vaginal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides.
In addition to the formulations described previously, the compounds may also be formulated as a depot preparation. Such long acting formulations may be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.
The pharmaceutical compositions also may comprise suitable solid or gel phase 3o carriers or excipients. Examples of such earners or excipients include but are not limited _70_ to calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as polyethylene glycols.
Suitable liquid or solid pharmaceutical preparation foams are, for example, aqueous or saline solutions for inhalation, microencapsulated, encochleated, coated onto microscopic gold particles, contained in liposomes, nebulized, aerosols, pellets for implantation into the skin, or dried onto a sharp object to be scratched into the skin. The pharmaceutical compositions also include granules, powders, tablets, coated tablets, (micro)capsules, suppositories, syrups, emulsions, suspensions, creams, drops or preparations with protracted release of active compounds, in whose preparation IO excipients and additives and/or auxiliaries such as disintegrants, binders, coating agents, swelling agents, lubricants, flavorings, sweeteners or solubilizexs are customarily used as described above. The pharmaceutical compositions are suitable for use in a variety of drug delivery systems. For a brief review of methods for drug delivery, see Langer, Scieyaee 249:1527-1533, 1990, which is incorporated herein by reference.
The compositions may conveniently be presented in unit dosage form and may be prepared by any of the methods well known in the art of pharmacy.
Other delivery systems can include time-release, delayed release or sustained xelease delivery systems. Such systems can avoid repeated administrations of the compounds of the invention, increasing convenience to the subject and the physician.
2o Many types of release delivery systems are available and known to those of oxdinary skill in the art. They include polymer based systems such as polylactic and polyglycolic acid, polyanhydrides and polycaprolactone; nonpolymer systems that are lipids including sterols such as cholesterol, cholesterol esters and fatty acids ox neutral fats such as mono-, di and triglycerides; hydrogel release systems; silastic systems;
peptide based systems; wax coatings, compressed tablets using conventional binders and excipients, partially fused implants and the like. Specific examples include, but are not limited to:
(a) erosional systems in which the polysaccharide is contained in a form within a matrix, found in U.S. Patent Nos. 4,452,775 (Kent); 4,667,014 (Nestor et al.); and 4,748,034 and 5,239,660 (Leonard) and (b) diffusional systems in which an active component 3o permeates at a controlled rate thxough a polymer, found in U.S. Patent Nos.
3,832,253 (Higuchi et al.) and x,854,480 (Zaffaroni). In addition, a pump-based hardware delivery system can be used, some of which are adapted for implantation.
Controlled release of chondroitinase ABC I or GAG or GaIAG fragments can also be achieved with appropriate excipient materials that are biocompatible and biodegradable. These polymeric materials which effect slow release of the chondroitinase ABC I or GAG or GalAG fragments may be any suitable polymeric material for generating particles, including, but not limited to, nonbioerodable/non-biodegradable and bioerodable/biodegradable polymers. Such polymers have been described in great detail in the prior art. They include, but are not limited to:
to polyamides, polycarbonates, polyalkylenes, polyalkylene glycols, polyalkylene oxides, polyalkylene terepthalates, polyvinyl alcohols, polyvinyl ethers, polyvinyl esters, polyvinyl halides, polyvinylpyrrolidone, polyglycolides, polysiloxanes, polyurethanes and copolymers thereof, alkyl cellulose, hydroxyalhyl celluloses, cellulose ethers, cellulose esters, nitro celluloses, polymers of acrylic and methacrylic esters, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxy-propyl methyl cellulose, hydroxybutyl methyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, cellulose acetate phthalate, carboxylethyl cellulose, cellulose triacetate, cellulose sulfate sodium salt, poly (methyl methacrylate), poly(ethylmethacrylate), poly(butylmethacrylate), poly(isobutylmethacrylate), poly(hexlmethacrylate), poly(isodecylmethacrylate), poly(lauryl methacrylate), poly (phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate), poly(octadecyl acrylate), polyethylene, polypropylene polyethylene glycol), polyethylene oxide), polyethylene terephthalate), polyvinyl alcohols), polyvinyl acetate, poly vinyl chloride polystyrene, polyvinylpryrrolidone, hyaluronic acid, and chondroitin sulfate.
Examples of preferred non-biodegradable polymers include ethylene vinyl acetate, poly(meth) acrylic acid, polyamides, copolymers and mixtures thereof.
Examples of preferred biodegradable polymers include synthetic polymers such as polymers of lactic acid and glycolic acid, polyanhydrides, poly(ortho)esters, polyurethanes, poly(butic acid), poly(valeric acid), poly(caprolactone), 3o poly(hydroxybutyrate), poly(lactide-co-glycolide) and poly(lactide-co-caprolactone), and natural polymers such as alginate and other polysaccharides including dextran and cellulose, collagen, chemical derivatives thereof (substitutions, additions of chemical groups, for example, alkyl, alkylene, hydroxylations, oxidations, and other modifications routinely made by those skilled in the art), albumin and other hydrophilic proteins, zero and other prolamines and hydrophobic proteins, copolymers and mixtures thereof. In general, these materials degrade either by enzymatic hydrolysis or exposure to water in vivo, by surface or bulk erosion. The foregoing materials may be used alone, as physical mixtures (blends), or as co-polymers. The most preferred polymers are polyesters, polyanhydrides, polystyrenes and blends thereof.
A subject is any human or non-human vertebrate, e.g., monkey, dog, cat, horse, l0 cow, pig, mouse, rat.
The present invention is further illustrated by the following Examples, which in no way should be construed as further limiting. The entire contents of all of the references (including literature references, issued patents, published patent applications, and co-pending patent applications) cited throughout this application are hereby expressly incorporated by reference.
EXAMPLES
Example 1 Materials and Methods Subcloning of Chondroitirac~se ABC I from Proteus vulgar~is Genomic DNA was isolated from cultures of Proteus vulgaris (ATCC # 6896) using a DNeasy purification kit from Qiagen (Valencia, CA). Primers were designed based on the previously published sequence of the gene (NCBI nucleotide accession:
E08025) [13]. It has been previously reported that the active form of chondroitinase ABC I isolated from P. vulgaf-is is missing the N-terminal signal sequence [9].
Therefore, two 5' end primers were designed so as to generate a full length clone and a 3o truncated version of the gene by omitting 72 bases encoding the signal sequence. In order to facilitate cloning into a pET-28a vector (Novagen, Madison, WI), the forward primer was constructed so as to incorporate an Nde I restriction site, and the reverse primer had a BanzHI and a ~I'lzo I restriction site built in. 'The primers for cloning cABC I
have the sequences: 5'-CATATGCCGATATTTCGTTTTACTGCA-3' (SEQ ID NO: 25) (forward primer for full length gene), 5'-CATATGCCCACCAGCAATCCTGCATTTG
3' (SEQ ID NO: 26) (forward primer for truncated gene) and 5' GGATCCTCGAGTCAAGGGAGTGGCGAGAGTTTG-3' (SEQ ID NO: 27) (reverse primer). PCR was run using P. vulgaYis genomic DNA as the template and a slightly longer extension time (3 min.) was used to account for the length of the gene (2994 bp) l0 being amplified.
The PCR product was initially ligated into the pCR~ 4-TOPO vector using the TOPO TA Cloning Kit (Invitrogen, Carlsbad, CA) and transformed into TOP10 E.coli cells. Plasmid DNA was isolated from positive colonies and the cABC I gene was excised from the TOPO vector using the previously engineered Nde I and X7zo I
restriction sites. The excised gene was ligated into pET-28a that had been digested with the same restriction enzymes. The ligation products were then transformed into DHSoc E, coli cells and plasmid DNA isolated from the colonies was screened by restriction digestion for incorporation of the cABC I gene. Plasmid DNA isolated from the positive colonies was also sequenced to confirm incorporation of the gene.
Site-Directed Mutagenesis Studies The QuikChange Site-Directed Mutagenesis Kit (Stratagene, La Jolla, CA) was used with plasmid DNA template to produce mutants of cABC I. Briefly, mutants were produced by plasmid denaturation and annealing of complementary oligonucleotide primers containing the desired mutation. This was followed by extension of the primers with a temperature cycler and PfuTurbo DNA polymerise, resulting in a mutated plasmid with staggered nicks. Digestion of hemi-methylated DNA of the parental template with Dpn I endonuclease selects for the mutation-containing synthesized DNA.
Primer sequences for mutagenesis studies are presented in Table 1. The mutated 3o plasmids were transformed into XLl-Blue supercompetent cells. The plasmids were prepared using a miniprep kit (Qiagen). Each clone was sequenced to confirm the presence of the desired mutation. Plasmid DNA was used to transform BL21 (DE3) E.
coli.
Table 1: Summary of Primer Sequences for Site-Directed Mutagenesis Studies Mutant Primer Pair Sequencesa Thr154A1a 5'-ACTGGCTGGCGTGCTGTGGGAGTCTCT-3' (SEQ ID NO: 28) 5'-AGAGACTCCCACAGCACGCCAGCCAGT-3' (SEQ ID NO: 29) V a1309I1e 5'-GGAACGCAAGGCAGACATCTGATCACTGATAAACAAATC-3' (SEQ ID NO: 30) 5'-GATTTGTTTATCAGTGATCAGATGTCTGCCTTGCGTTCC-3' (SEQ ID NO: 31) Pro322Leu 5'-CAACCAGAGAATCTTAACTCTCAAGATAAACAACTATTTG-3' (SEQ ID NO: 32}
5'-CAAATAGTTGTTTATCTTGAGAGTTAAGATTCTCTGGTTG-3' (SEQ ID NO: 33) Pro694G1n 5'-GGTTGGGATTGGAATAGAATGCAAGGGGCAACCACT-3' (SEQ ID NO: 34) 5'-AGTGGTTGCCCCTTGCATTCTATTCCAATCCCAACC-3' (SEQ ID NO: 35) His501A1a 5'-TGATGGTACAGCATGGCGAGCTGAAGGCAACTATCCGGGCTA-3' (SEQ ID NO: 36) 5'-TAGCCCGGATAGTTGCCTTCAGCTCGCCATGCTGTACCATCA-3' (SEQ ID NO: 37) Tyr508A1a 5'-GGCAACTATCCGGGCGCCTCTTTCCCAGCC-3' (SEQ ID NO: 38) 5'-GGCTGGGAAAGAGGCGCCCGGATAGTTGCC-3' (SEQ ID NO: 39) Arg560A1a 5'-CCGCTTGCAGGAGCACACCCTTTTAACTCACCTTCG-3' (SEQ ID NO: 40) 5'-CGAAGGTGAGTTAAAAGGGTGTGCTCCTGCAAGCGG-3' (SEQ ID NO: 41) G1u653A1a 5'-CACCAATGTTTGGTCATCTGCAATTTATAACAAAGATAACCGT-3' (SEQ ID NO: 42) 5'-ACGGTTATCTTTGTTATAAATTGCAGATGACCAAACATTGGTG-3' (SEQ ID NO: 43) His561A1a 5'-CCGCTTGCAGGAAGAGCCCCTTTTAACTCACCTTCG-3' (SEQ ID NO: 44) 5'-CGAAGGTGAGTTAAAAGGGGCTCTTCCTGCAAGCGG-3' (SEQ ID NO: 45) His712A1a 5'-GACAGTCCTAAACCTGCTACCTTAATGCAACGTGGAGAG-3' (SEQ ID NO: 46) 5'-CTCTCCACGTTGCATTAAGGTAGCAGGTTTAGGACTGTC-3' (SEQ ID NO: 47) Arg500A1a 5'-CCTGATGGTACAGCATGGGCACATGAAGGCAACTATCCGGGC-3' (SEQ ID NO: 48) 5'-GCCCGGATAGTTGCCTTCATGTGCCCATGCTGTACCATCAGG-3' (SEQ ID NO: 49) a Mutation codons are indicated in bold; bases modified in order to create the desired point mutations are underscored. Forward primers for each mutant are listed first.
Recornbizzant Expression arzd Protein Pur-ificatiorz of Chohdv~oitirzase EIBC
I and lLfzztants Recombinant cABC I and the site-directed mutants were expressed in E. coli and purified essentially as previously described [8]. Cultures for expression contained 40 ~,g/ml kanamycin. The presence and purity of the proteins were assessed by SDS-lo polyacrylamide gel electrophoresis analysis using precast Invitrogen NuPAGE
12% Bis-Tris gels, the XCell SureLock Mini-Cell, and Simply Blue SafeStain (Invitrogen). A
relative protein concentration was calculated using the Bradford assay (Bio-Rad Laboratories, Hercules, CA) with bovine serum albumin (Sigma, St. Louis, MO) as a standard. The 6x His tag was cleaved using the Thrombin Capture Kit (Novagen, San Diego, CA) as previously described [17].
Structural Clzar-acterizatiorz Circular dichroism (CD) spectra were recorded at 25°C on an Aviv spectrophotometer using Quartz cuvettes with optical path length of 0.1 cm.
Scans were collected between 300 and 195 nm with a 1.0-nm bandwidth and a scan rate of 1 nm/min. Three scans were averaged for each protein. For melting experiments, spectra were collected at 5°C intervals from 5°C to 80°C.
Recombinant proteins were concentrated and buffer-exchanged into 50 mM sodium phosphate pH 7.5 using Centricon 10 filters (Millipore, Billerica, MA). Protein content was quantified by standard methods using the Bio-Rad Protein Assay Kit (Bio-Rad Laboratories).
All spectra were collected using a protein concentration of 0.2 mg/ml. The buffer contribution was accounted for in all spectra. The signal was normalized to molar ellipticity, 8M, in degrees~cmZ~dmol-1.

Deter°rnirratiora of Optirraal Biochernical Conditions for Recombinant Claorrdroitinase ABC I Activity For these studies C6S and DS were dissolved at a 1 mg / mL concentration in various buffers in an attempt to determine the relative effects of pH, temperature, ionic strength and sodium acetate concentration on enzyme activity. The activity of a fixed amount of recombinant active cABC I (0.2 ~,g) was assessed based on the change in absorbance at 232 nm per minute (dA2sz / min) as reaction conditions were varied. The effect of pH was investigated by using 2 different buffer systems: (1) 50 mM
sodium phosphate pH 6.5, 7.0, 7.5, 8.0, 8.5, 9.0 and (2) 50 mM Tris pH 7.5, 8.0, 8.5, 9Ø
to Activity at various temperatures (25 °C - 45 °C) was also investigated. To determine the relative effect of ionic strength, the NaCl concentration was varied from 0 -1.0 M in 50 mM Tris buffer (pH 8.0). Previous studies have suggested that addition of sodium acetate to the buffer enhances the activity of cABC I [9~. To confirm this we varied the sodium acetate concentration from 0 - 0.5 M in 50 mM Tris buffer (pH 8.0).
The temperature study was carried out using a temperature-controlled UV
spectrophotometer (DU 800, Beckman Coulter, Fullerton, CA) in a quartz cuvette at a 1 mL final reaction volume. The other optimization experiments were carned out on a SpectraMax 190 (Molecular Devices, Sunnyvale, CA) using a 96-well quartz plate.
Eight enzyme reactions (i.e. 1 column of the plate) could be initiated and monitored 2o simultaneously using our setup. This semi-high throughput approach enabled us to sample multiple reaction conditions in an easily repeatable manner. The temperature on the SpectraMax was set to 37 °C for these experiments. Absorbance at 232 nm was monitored for 2 - 4 min, and activity was calculated based on the initial rate of product formation.
Product Profile Analysis Capillary electrophoresis (CE) was performed using similar conditions to those developed for the separation of heparan sulfate GAG disaccharides [18].
Briefly, 100 ~.l of 100 ~g/ml substrate was placed in a reaction vial with 1 ~.g of enzyme and incubated 3o at 37°C overnight. Substrates used included C6S from from shark cartilage (Sigma), DS
from porcine intestinal mucosa (Sigma), and C4S from sturgeon notochord (Seikagaku, _77_ Tokyo, Japan). Uncoated fused silica capillaries (i.d. of 75 l.un and It°t of 80.5 cm) coupled with an extended path detection cell were used on a Hewlett-Packard 3oCE unit.
Di- and oligosaccharides were detected at 232 nm using an electrolyte solution of 50 mM
Tris/phosphoric acid, pH 2.5. Dextran sulfate was added to the buffer to suppress nonspecific interactions with the fused silica wall of the capillaries.
Electrophoretic separation was performed using reverse polarity at a voltage of -30 kV. Peak identities were confirmed by co-migration with known standards.
Clao~droitinase ABC' I Activity Analysis l0 Two w1 of enzyme were placed in 248 ~.l of 50 mM Tris-HCl, 50 mM sodium acetate, pH 8.0 with 1 mg/ml of substrate (0.25 mg/ml for hyaluronan) at 37°C. Product formation was monitored as an increase in absorbance at 232 nm as a function of time in our semi-high throughput format. Initial rates represent < 10°l°
substrate turnover.
Chondroitinase ABC (protease free) was purchased from Seikagaku. Substrates used in these studies are described above and additionally include chondroitin from shark cartilage (Seikagaku), hyaluronan from human umbilical cord (Sigma), heparin (Celsus, Cincinnati, OH), and heparan sulfate (Celsus). The quantity of enzyme used in each reaction was measured using the Bio-Rad protein assay kit. A kinetic analysis of cABC I
employed our semi-high throughput spectrophotometric approach and is essentially as 2o previously described [19]. One ~l of 0.2 ~.gl~l cABC I was added to 249 ~l of a solution containing different concentrations of GaIAG substrates (C4S, C6S and DS) in 50 rnM
Tris-HCI, 50 mM sodium acetate, pH 8Ø Each well contained different substrate concentrations ranging from 0.1 to 5 mg/rnl. Product formation was monitored by measuring the absorbance at 232 nm every 2 seconds.
To evaluate the kinetic data, the initial reaction rate (vo) was first determined from the value of the slope from the plot of product formation as a function of time. The values of Y,~,~ and K", were extracted from the slope and y-intercept of the Hares plot generated by monitoring the product formation and using Equation 1 below:

_78_ ~sVbsl = Yl ~subsl+ ~ "' Equation 1, where [subs] represents a mar mar the substrate concentration.
The k~at was calculated by dividing Y",~ by the cor~centration of enzyme in the reaction. A molar absorptivity coefficient (g) for the product of the enzymatic reaction of 3,800 M-lcrri I was used. The calculated value for the path length of the well using 250 ~,l volume for the reaction was 0.904 cm. The analyses were performed in triplicate.
Results to Cloning of the Chondroitizzase AB'C t Gene frozn the Proteus vulgaris Gezzofzze The gene for cABC I was cloned from P. vulgaris genomic DNA as a full-length version and the mature enzyme, without its putative leader sequence. The PCR
product of approximately 3 kb was subcloned into pET-28a, via arr intermediate TOPO
cloning step, to facilitate its incorporation and expression in E. coli_ Chondroitinase ABC I was expressed in E. coli as previously described, with an N-terminal 6x histidine tag. The histidine tag enabled quick purification of the enzyme over a charged Ni+Z
column.
Expression of the initial clone resulted in an enzyme with low activity against GaIAG
substrates.
DNA sequencing analysis revealed a number of differences between our sequence and the previously published sequence of the gene by Sato et al (NCBI
nucleotide accession: E08025) [13]. The major irregularity was observed in the resulting amino acid sequence between residues 494 - 530, which can be attributed to a pair of frame-shift errors in the published DNA sequence [13]. After position 1771 there should be an additional cytosine (C) base in the published sequence (CGC CCT G
instead of CGC CTG), that would result in a proline instead of a leucine at position 494.
At position 1870 there is an additional thyrnidine (T) base which should be removed (TCA
GTG GGT instead of CAG TTG GGT), thereby resulting in a better alignment between the published sequence and our cloned sequence. Other errors in the Sato et al sequence [13] produce differences in amino acids at positions 125 (Pro instead of Leu}, 369 (Val _79_ instead of Met), 670 (Gly instead of Ala) and 865 (Arg instead of Ser). These errors in the previously published sequence have also been observed by Huang et al [
11].
The clone produced Was in close agreement to the Ryan et al. sequence.
However, there were four point mutations present in the clone at variance with the sequence suggested by Ryan et al [14]. At amino acid position 154, an ACT
colon produces a threonine residue instead of an alanine residue (GCT). At position 309, our clone contains a GTC colon yielding a valine residue, instead of isoleucirie (ATC). At position 322, a CCT colon gives proline instead of a leucine (CTT) residue.
And, at position 694, a CCA colon generates a proline residue instead of glutaznine (CAA).
1o Since expression of the initial clone resulted in a low activity enzyme, these point mutations were "repaired" using site-directed mutagenesis techniques. All four point mutations were corrected sequentially so as to conform precisely with the protein sequences reported in the crystal structure [I 1] and by Ryan et al [14].
I5 Recoj~abi~zafat Expression a~zd PurifzcatioTa of Claorzdroitiraase ABC f To establish the functionality of the "fixed" cABC I clone, the protein in E.
coli was recombinantly expressed. Expression of the original full-length clone generated an enzyme almost wholly present in the insoluble fraction. The yield of soluble recombinant enzyme was greatly improved by the engineered removal of the 20 hydrophobic N-terminal signal sequence. This result is consistent with other GAG-degrading enzymes studied [8]. This sequence tag is most likely responsible for targeting to a specific location in the periplasm. Chondroitinase ABC I
purification generally yielded upwards of 35 mg of protein from 500 ml of culture (Table 2). SDS-PAGE analysis (Fig. 1) revealed a highly pure band at 110 kDa, in close agreement 25 with previously reported masses of cABC I [9, 13] and its theoretical mass 112,614 Da based solely on amino acid composition.
Table 2: Puribcation of Recombinant Chondroitinase ABC I
Specific activity Fraction Protein yield x-fold Purificationa (1 mg/ml C6S) (mg) (Units / mg) Crude lysate I95 92.I
Elution from Ni+2 35 197.9 2.1 column Thrombin cleavageb 3S 230.6 2.5 The x-fold purification was determined relative to the specific activity measured for crude lysate.
b Cleavage of the 6x His tag from the recombinant protein was confirmed by Western blot analysis using an anti-His tag antibody (Amersham Biosciences, Piscataway, NJ). No detectable difference in activity against GaIAG substrates was observed between the recombinant cABC I and its His tag-cleaved counterpart.
A check for the absorbance at 232 nm, suggestive of the double bond formed in the degradation reaction, was performed spectrophotometrically with 5.0 ~.g of each recombinant enzyme (the original and the clone that underwent mutagenesis repair) and 1 mg/ml C6S or DS. Expression and purification of the "fixed" truncated clone restored robust processing activity against a variety of GAG substrates. The original enzyme showed a low level of activity against both of the GaIAG substrates, whereas the "fixed"
version acted on both C6S and DS at healthy rates.
Biochefnical Conclitions for Optifnal in VitYO Activity Having established the broad substrate specificity of the recombinant cABC I, the reaction conditions were then optimized so as to achieve maximal enzyme activity.
These parameters included temperature, pH, ionic strength, and dependence on sodium acetate. A Tris buffer system was chosen, as it resulted in a greater relative acti~-ity than 2o phosphate buffer. The enzyme displayed maximal activity at pH 8.0 and was essentially inactive for both C6S and DS at pH 9.0 (Fig. 2).
The recombinant enzyme's activity against C6S and DS was also examiried with regard to ionic strength. Recombinant cABC I was optimally active at 62.5 naM
NaCl for C6S and 125 mM for DS. For C6S, 50% inhibition occurred at slightly more than 125 mM NaCI, with activity virtually ablated at 400 mM NaCI. For DS, 50%
inhibition occurred at under 250 mM NaCI, and activity was essentially negligible over 500 mM
NaCI.
In terms of temperature optima, with C6S as the substrate, the recombinant enzyme demonstrated maximal activity at 37°C. At slightly over 40°C, enzyme activity was 50% inhibited, and activity fell dramatically at 45°C. For DS, a greater level of enzyme activity was evident over the range from 25°C to 40°C, with an optima between 30°C and 37°C. At 45°C, processing of DS by the recombinant cABC I was inhibited by over 60%. For both GaIAG substrates, 37°C was chosen as the optimal temperature for to biochemical experiments.
It has previously been reported that acetate promotes cABC I activity [9]. Our investigation found that 50 mM sodium acetate provided optimal activity with C6S as tl~e substrate, and 100 mM sodium acetate with DS as the substrate. An absence of sodium acetate in the reaction buffer inhibited enzyme activity against C6S by ~50%
and resulted in an almost complete decline in activity against DS.
Choyadroitiraase ABC I Activity Analysis The specific activity of recombinant cABC I acting on various substrates (Table 3) was determined by monitoring the increase in absorbance at 232 nm for 5 minutes.
2o The initial rate of increase in Az3z was determined for each substrate. The enzyme activity in units (1 U = 1 pmole product formed / min.) was calculated from the initial rate using s = 3800 M-1 for reaction products at pH 8Ø Recombinant chondroitinase ABC I shows maximum activity on C4S. Specific activity values for C6S and DS
are lower and suggest a slight preference for C6S as compared to DS. Other chondroitin substrates are processed at comparable, albeit much lower rates (Table 3). The enzyme shows very low activity against hyaluronan and was inactive against heparin and heparan sulfate substrates. These results are consistent with previously reported data for the chondroitinase ABC I enzyme purred from P. vulgaris and available commercially as "protease-free chondroitinase ABC" from Seikagaku [9].

_82_ Table 3: Specific Activity of Recombinant Chondroitinase ABC I on Glycosaminoglycan Substrates Substrate Speeif>~c activity (Units/mg protein) Chondroitin-4-sulfate 290.8 Chondroitin-6-sulfate 1'4.6 Dennatan sulfate 122.3 Chondroitin 69.8 Chondxoitin sulfate D 54.2 Chondroitin sulfate E 34.8 Hyaluronan 14-.8 Heparin/Heparan sulfate n _d.

Kinetic parameters were determined for recombinant cABC I against C6S, DS and substrates and are summarized in Table 4. The kinetic analysis corroborates the specific activity results, wherein cABC I seems to prefer C4S a_nd C6S over DS (Fig.
3).
Table 4: Kinetic Analysis of Chondroitinase ABC I with Various Substratesa l0 Substrate I~" fat fat/ ~m ~,M miri N,M- miri Chondroitin-6-Sulfate1.2 ~ 0.6 37362~ ~ 6538 32162 Dermatan Sulfate 2.5 ~ 0.5 2710 ~ 2527 10727 Chondroitin-4-SulfateI.5 ~ 0.1 52263. ~ 1344 35920 a Values are the mean of at least three experiments ~ standard deviation.
The specific activity of the recombinant active chondroitinase ABC I was also compared with the commercially available purified "protease-free" cABC I from Seikagalcu. Rate of product formation (~1A232 l min) was measured for 2 - 4 min. at 37 °C using a 1 mg / mL C6S solution in 50 mM Tris buffer (pH 8.0) containing 50 mM
sodium acetate. The Bradford assay was used to calculate the amount of protein present in each sample. Based on the results our recombinant enzyme gave us a specific activity value of 164.2 mU / p.g, whereas the Seikagaku enzyme had a specific activity of 20.2 mU / p,g. The difference in specific activity could be the result of enzyme stability or storage conditions.
The activity of cABC I on these three substrates was also analyzed by CE. This study represented an end-point assay for activity and allowed for a characterization of the final products of cABC I digestion on alI of the substrates after an 18 hour incubation at 37 °C. For C4S and C6S, the product profile shows predominantly disaccharide products with minor tetrasaccharide products also detected (Fig. 4). In both of these cases the 1o respective monosuIfated disaccharide (i.e., tiUA-GalNAc4S or QUA-GalNAc6S) represents the major product. In the case of DS a mixture of disaccharides and tetrasaccharides is observed as the final product of digestion. However, one of the tetrasaccharide peaks is much larger than those observed for the C4S and C6S
substrates.
This suggests that there may be some resistance by tetrasaccharide fragments within DS
to cleavage by cABC I. The structure of the resistant tetrasaccharide was determined to be 4UA-GalNAc4S-IdoA-GalNAc4S based on co-elution (on CE) with a previously isolated pure dermatan tetrasaccharide having the same structure. In order to confirm that this tetrasaccharide is indeed resistant to cABC I action, the pure tetrasaccharide was incubated with enzyme at 37 °C, and the resulting products were analyzed by CE. The 2o CE trace showed that there is no breakdown of the tetrasaccharide, thereby confirming that cABC I cannot degrade this tetrasaccharide fraction in DS. The diminished ability of the recombinant cABC I to cleave DS tetrasaccharides is consistent with previous reports on cABC I action pattern [9].
Mutagenesis Studies A comparison between the crystal structures of F. hepar-irauna cAC arid P.
vulga~~is cABC I revealed a similar linear arrangement of domains that are supe~cially similar in terms of overall structure. On a closer inspection of the catalytic domain of cAC with the middle domain of cABC I, a paucity of sequence identity can be observed.
3o This is consistent with the exception of the several amino acid residues that have previously been implicated as active site players in cAC [20] and that seem to have counterparts in cABC I. Using this framework of potential conserved catalytic active site residues, site-directed mutagenesis studies were undertaken to probe the importance of several residues in enzyme activity. His501, Tyr508, GIu653, and Arg560 were all mutated to alanine and characterized in activity experiments. 'These residues were previously suggested by Huang et al [11) and could constitute the active site, whereby the proton acceptance and donation mechanism could take place [21]. The general reaction requires a residue with positive character to stabilize the uronic acid carboxylate group, a general base with which to abstract a proton from the ~zronic acid C5 and a residue capable of proton donation to the glycosidic oxygen in the elimination phase of the reaction. Since a general base, like histidine, is believed to bei a key component for this catalysis, histidine residues (His56I and His712) were also mutated.
These residues are not conserved between the two enzymes but are in close proximity to the proposed active site.
Examination of the mutant enzymes in an end-point assay by CE demonstrated a number of residues which seem to be important to catalysis. HLS501A1a produced no products on overnight digestion with C6S, DS, or C4S as the substrate (Fig.
5). This is in sharp contrast with His561A1a and His712A1a, which both produced a product profile comparable to recombinant active cABC I against all three of these GalAGs after an overnight digestion. Tyr508A1a, G1u653A1a, and Arg560A1a alL were unable to yield 2o products in an exhaustive digestion with any of these substrates. These observations provide direct evidence that His501, Tyr508, G1u653, and Arg560 are important for the activity of recombinant cABC I. The relative positions between these residues within the active site cleft of cABC I lends further credence to the notion of this amino acid grouping as the enzyme active site.
Circular dichroism spectroscopy was used to analyze -the overall secondary structure of the proteins. The resulting spectra displayed a high a-helix and (3-sheet content (Fig. 6). These results are in agreement with the crystal structure of cABC I
[11]. CD analysis was also used to confirm that the loss of activity displayed by the mutants (His501AIa, Tyr508A1a, G1u653A1a, and Arg560AIa~ was not due to an 3o alteration of the overall secondary structure of the protein. As shown in Fig. 5, no significant differences on the CD spectra between the mutants and the recombinant cABC I were observed. To further address the effect of mutations on protein stability, heat denaturation studies were used to compare the recombinant enzyme to its mutants.
All proteins displayed melting transitions of 455 °C (Fig. 6, inset).
Although these results do not exclude the possibility of minor structural perturbations in the local environment, they do suggest that the overall structure and stability of the protein are not compromised when these particular residues are mutated to alanine.
Table 5: Activity Analysis of Chondroitinase ASC I Mutantsa cABC I Mutant C6S Kinetics DS Kinetics Activity on C.E. b ~at ~m scat HSOlA n.d. n.d. n.d. n.d. - - -H561A 15.2 39103 6.9 3969 + + +

H712A 8.6 1140 5.1 613 + + +

Y508A n.d. n.d. n.d. n.d. - - -R537A n.d. n.d. n.d. n.d. - -R477A 19.9 419 3 5.7 162 + + +

E653A n.d. n.d. n.d. n.d. - - -Kinetic parameters are reported (k~~t). n.d., activity was in pM (Km) and miri too low to be detected.
b (+) refers to an exhaustive digestion of the substrate; (-) indicates that no products were detected. ~ The R537A mutant did display some residual activity on DS.

Table 6: Kinetic Analysis of cASC I and Mutants with C6S as Substrate EriZylTle Km Kcat ~cat~ Km E,iM miri 1 EtM-1 miri I
2o Chondroitinase ABC I 1.2 37362 32162 His501A1a or Lys or Arg na na na Tyr508A1a na na na Tyr508Phe 36.4 31.2 0.9 Arg560A1a na na na G1u653A1a or Asp na na na G1u653G1n 6.1 1607.6 262.1 Arg500A1a 19.9 418.6 21.0 Table 7: Kinetic Analysis of cABC I and Mutants with DS as Substrate Enzyme Km Kcat Kcat~ Rm N,M miri 1 E.vM-I miri 1 Chondroitinase ABC 2.5 27102 10727 I

His501A1a or Lys or na na na Arg Tyr508A1a na na na Tyr508Phe 48.9 104.8 2.11 Arg560A1a na na na G1u653A1a or Asp na na na G1u653 Gln 4.16 5174. 8 1245 2o Arg500A1a 35.68 162.0 4.54 Discussion The sub-cloning of the cABC I gene from P. vulgaris and its recombinant expression in E. coli are described herein. This recombinant cABC I was also examined biochemically, providing the first conclusive evidence of the residues that constitute the enzyme active site. The establishment of a well-characterized enzyme with defined GaIAG substrate specificity provides insight into structure-function relationships in biology.
3o Purification of cABC I directly from cultures of P. vulgaris resulted in preparations with low yields and considerable protease contamination [22, 23].
These conditions spurred investigators toward recombinant production approaches.
Early attempts to recombinantly express cABC I in E. coli were laden with di~culty.
Expression of a soluble protein was hampered by both the size of the gene and the signal sequence. Random proteolysis also proved to be a nuisance to achieving the recombinant protein, and this complication has been observed previously [13].
The one-step purification process described allowed for the preparation of an abundance of _87_ soluble protein. Sequence anomalies in the original clone suggest that there may have been underlying structural changes responsible for this eradication of enzyme activity.
The sequential repair via site-directed mutagenesis of the original truncated clone was accompanied by a restoration of enzyme activity. Indeed, the "repaired"
recombinant enzyme was able to process C4S, DS, and C6S at robust rates. It was also able to degrade a variety of other GaIAG substrates and hyaluronan at lesser rates. It is clear that the recombinant active cABC I described possessed a specific activity that far exceeded that of the commercially-available enzyme. Therefore it is evident that the cloning, expression, and purification system provided does not at alI
compromise the to activity of the cloned enzyme. It is possible that the disparity in specific activities between the recombinant enzyme and the commercially-available cABC I is the result of different purification and storage practices rather than intrinsic enzymatic properties. It is also feasible that an overestimation of active protein content for the commercial enzyme led to a dramatically diminished observed rate, as some portion of quantified protein may have been distorted in the isolation process.
The optimal conditions for activity of recombinant cABC I are similar to those obtained for the purified enzyme. However, it was also observed that different buffer systems affect the processing activity on different substrates. For enzyme activity on C6S in 50 mM sodium phosphate, the optimal pH was determined to be pH 7.0;
2o however, in 50 mM Tris buffer optimal activity was observed at pH 8Ø This discrepancy was not observed with DS as substrate, where the activity maximum was at pH 8.0 regardless of the buffer system. In both cases, however, the enzyme showed more activity in Tris buffer than sodium phosphate. It was also observed that there was a slight inconsistency in the concentration of NaCI and sodium acetate required for maximum activity on C6S as compared to DS. For DS, a higher concentration (approximately double) of both NaCI and sodium acetate in the buffer showed the highest activity in terms of product formation. Another interesting observation is the importance of the presence of salt (i.e., either NaCI or sodium acetate) in the buffer system for activity of recombinant cABC I on DS. From Fig. 2 (panels C and D) it can 3o be seen that in the absence of any salt in the buffer the enzyme activity on DS is about _88_ 5% of the observed maximum activity. However, with C6S as substrate, even when there is no salt in the buffer, 50 - 60% of the maximum activity was observed.
It could be that the salt requixement for DS is important in abolishing non-specific interactions of this substrate with the enzyme. Dermatan sulfate has considerable intrinsic flexibility due to the presence of iduronic acid in its structure.
Therefore, it can potentially display a wider range of interactions than C6S
and may bind to positively charged patches on the surface of the enzyme, rather than in the active site.
In the presence of salt, these non-specific interactions would be markedly reduced.
The results with CE indicate that cABC I was unable to cleave a tetrasaccharide l0 fragment within DS and this fragment was identified to be QUA-GalNAc4S-IdoA-GalNAc4S. This is in contrast to the product profile obtained on treating DS
with cB, where the major products are predominantly disaccharides [19J. cABC I and cB
have totally different structures and, therefore, may bind to and process DS very differently.
The crystal structure of cABC I [11J revealed a three domain protein. The middle domain contains the catalytic site in a wide-open cleft. Despite very limited sequence homology with the catalytic domain of F. laepa~ifaum cAC, this middle domain of cABC
I did contain a conserved grouping of residues that were implicated in catalysis in cAC
[20]. These cABC I residues were His501, Tyr508, Arg560, and G1u653.
Manipulation of these residues via mutagenesis to alanine resulted in knockout proteins -enzymes with 2o a complete inability to degrade GAG substrates. Thus this tetrad of residues is important for enzyme activity. With regard to the (3-elimination mechanism previously suggested for GAG lyases, it seems that this group of residues is potentially capable of performing the stabilization and proton shuffling responsibilities required for GAG
degradation.
This study provides the first experimental evidence that this grouping of amino acids comprises the cABC I active site.
It was demonstrated that His501 was, in fact, the histidine important in catalysis.
Two other histidines were examined, His561 and His712. Alanine mutants of these residues demonstrated that these histidines were not critical for GAG
degradation. In fact, on an exhaustive digestion with GaIAG substrate, these mutants both provided a full 3o product profile.

_89_ Previously, it was suggested that Arg500 was essential for cABC I's ability to process both CS and DS [11]. Arg500's sidechain was predicted to be positioned toward the uronate carboxylate group of either substrate, serving some role in charge neutralization. However, our product profile analysis and specific activity determinations with the mutant Arg500A1a suggest that this residue is not actually critical for catalysis. In fact, with C6S, C4S, and DS, an exhaustive digestion with Arg500A1a resulted in a product profile virtually indistinguishable from those generated with our recombinant cABC I.
Chondroitinase ABC I's broad substrate specificity complicates fine 1o understanding of its GAG degradation mechanism. The studies provided herein outline the cloning and expression of cABC I, provide a biochemical characterization of this enzyme, and offer the first conclusive proof of the active site. This will advance GAG
sequencing biotechnology. The sequencing of GAGS remains a challenging enterprise.
Isolating pure GAGS in sufficient quantity for analysis is technically difficult for a variety of reasons, including GAG structural heterogeneity and high negative charge.
Enzymatic tools, when used in conjunction with analytical approaches such as coupled mass spectrometry/capillary electrophoresis, have allowed for the rapid and precise elucidation of biologically relevant GAGS using a bare minimum of material [5, 18].
The thorough characterization of new tools, especially GAG-degrading enzymes, will 2o extend the scope and rigor of GAG sequencing.
References for Example 1 1 Bernfield, M., Gotte, M., Park, P. W., Reizes, O., Fitzgerald, M. L., Lincecum, J.
and Zako, M. (1999) Functions of cell surface heparan sulfate proteoglycans, Annu Rev Biochem 68, 729-777 2 Sugahara, K., Mikami, T., Uyama, T., Mizuguchi, S., Nomura, K, and Kitagawa, H. (2003) Recent advances in the structural biology of chondroitin sulfate and dermatan sulfate. Curr Opin Struct Biol 13, 612-620 3 Bao, X., Nishimura, S., Mikami, T., Yamada, S., Itoh, N. and Sugahara, K.
(2004) Chondroitin sulfate/dermatan sulfate hybrid chains from embryonic pig bxain, which contain a higher proportion of L-iduronic acid than those from adult pig brain, exhibit neuritogenic and growth factor binding activities. J Biol Chem 279, 9765-9776 4 Ernst, S., Langer, R., Cooney, C. L. and Sasisekharan, R. (1995) Enzymatic degradation of glycosaminoglycans. Crit Rev Biochem Mol Biol 30, 387-444 5 Venkataraman, G., Shriven Z., Raman, R. and Sasisekharan, R. (1999) Sequencing complex polysaccharides. Science 286, 537-542

6 Sasisekharan, R., Bulmer, M., Moremen, K. W., Cooney, C. L. and Langer, R.
(1993) Cloning and expression of heparinase I gene from Flavobacterium 1o heparinum. Proc Natl Acad Sci U S A 90, 3660-3664

7 Godavarti, R., Davis, M., Venkataraman, G., Cooney, C., Langer, R. and Sasisekharan, R. (1996) Heparinase III from Flavobacterium heparinum: cloning and recombinant expression in Escherichia coli. Biochem Biophys Res Commun 225, 751-758

8 Pojasek, K., Shriver, Z., Kiley, P., Venkataraman, G. and Sasisekharan, R.
(2001) Recombinant expression, purification, and kinetic characterization of chondroitinase AC and chondroitinasc B from Flavobacterium heparinum.
Biochem Biophys Res Commun 286, 343-351

9 Hamai, A., Hashimoto, N., Mochizuki, H., Kato, F., Makiguchi, Y., Horie, K.
and 2o Suzuki, S. (1997) Two distinct chondroitin sulfate ABC lyases. An endoeliminase yielding tetrasaccharides and an exoeliminase preferentially acting on oligosaccharides. J Biol Chem 272, 9123-9130

10 Huang, W., Matte, A., Li, Y., Kim, Y. S., Linhardt, R. J., Su, H. and Cygler, M.
(1999) Crystal structure of chondroitinase B from Flavobacterium heparinum and its complex with a disaccharide product at 1.7 A resolution. J Mol Biol 294,

11 Huang, W., Lunin, V. V., Li, Y., Suzuki, S., Sugiura, N., Miyazono, H. and Cygler, M. (2003) Crystal structure of Proteus vulgaris chondroitin sulfate ABC
lyase I at 1.9A resolution. J Mol Biol 328, 623-634

12 Fethiere, J., Eggimann, B. and Cygler, M. (1999) Crystal structure of chondroitin AC lyase, a representative of a family of glycosaminoglycan-degrading enzymes.
J Mol Biol 288, 635-647

13 Sato, N., Shimada, M., Nakajima, H., Oda, H. and Kimuxa, S. (1994) Cloning and expression in Escherichia coli of the gene encoding the Proteus vulgaris chondroitin ABC lyase. App! Microbiol Biotechnol 4I, 39-46

14 Ryan, M. J., Khandke, K. M., Tilley, B. C. and Lotvin, J. A. (1994), (international application published under the patent cooperation treaty) WO

15 Bradbury, E. J., Moon, L. D., Popat, R. J., King, V. R., Bennett, G. S., Patel, P.
N., Fawcett, J. W. and McMahon, S. B. (2002) Chondroitinase ABC promotes functional recovery after spinal eoxd injury. Nature 416, 636-640

16 Morgenstern, D. A., Ashex, R. A. and Fawcett, J. W. (2002) Chondroitin sulphate proteoglycans in the CNS injury response. Prog Brain Res I37, 313-332

17 Myette, J. R., Shriven Z., Kiziltepe, T., McLean, M. W., Venkatararnan, G.
and Sasisekharan, R. (2002) Molecular cloning of the heparin/heparan sulfate delta 4,5 unsaturated glycuronidase from Flavobacterium heparinum, its recombinant expression in Escherichia coli, and biochemical determination of its unique substrate specificity. Biochemistry 4I, 7424-7434

18 Rhomberg, A. J., Ernst, S., Sasisekharan, R. and Biemann, K. (1998) Mass spectrometric and capillary electrophoretic investigation of the enzymatic degradation of heparin-like glycosaminoglycans. Proc Natl Acad Sci U S A 95,

19 Pojasek, K., Raman, R., Kiley, P., Venkataraman, G, and Sasisekharan, R.
(2002) Biochemical characterization of the chondroitinase B active site. J Biol Chem 277, 31179-31186

20 Huang, W., Boju, L., Tkalec, L., Su, H., Yang, H. O., Gunay, N. S., Linhardt, R.
J., Kim, Y. S., Matte, A. and Cygler, M. (2001) Active site of chondroitin AC
lyase revealed by the structure of enzyme-oligosaccharide complexes and 3o mutagenesis. Biochemistry 40, 2359-2372

21 Jedrzejas, M. J. (2000) Structural and functional comparison of polysaccharide-degrading enzymes. Crit Rev Biochem Mol Biol 35, 221-251

22 Oike, Y., Kimata, K., Shinomura, T. and Suzuki, S. (I980) Proteinase activity in chondroitin lyase (chondroitinase) and endo-beta-D-galactosidase (keratanase) preparations and a method to abolish their proteolytic effect on proteoglycan.
Biochem J 191, 203-207

23 Harrisson, F., van Hoof, J. and Vanroelen, C. (1986) On the presence of proteolytic activity in glycosaminoglycan-degrading enzyme preparations. J
Histochem Gytochem 34, 1231-1235 l0 Example 2 Materials and Methods Mczte~ials Porcine intestinal mucosa DS (average MW 35,000 g/mol) and shark cartilage C6S (average MW 50,000 g/mol) were purchased from Sigma. C4S (super special grade, average MW 50,000 g/mol) was purchased from Seikagaku/Associates of Cape Cod (Falmouth, MA). Oligonucleotides were purchased from Invitrogen. The QuikChange Site-Directed Mutagenesis I~it was purchased from Stxatagene. All other materials are from common sources or are as noted.
Sub-Clorzizzg and Site IDirected Mutagezzesis of c~4BC I
Genomic DNA was isolated from cultures of P>"oteus vulgaf~is (ATCC # 6896) using a Qiagen DNeasy purification kit. Sub-cloning procedures were as previously described [29] and above. The QuikChange Site-Directed Mutagenesis Kit was used to produce mutants of cABC I, as described above. Primer sequences for all studies are presented in Table 8. The plasmids were prepared using a miniprep kit (Qiagen). Each 3o clone was sequenced to confirm the presence of the desired mutation.
Plasmid DNA was used to transform BL21 (DE3) E. coli.

Table 8: Summary of Primer Sequences fox Site-Directed Mutagenesis Mutant Primer Pair Sequences a Thr154A1a 5'-ACTGGCTGGCGTGCTGTGGGAGTCTCT-3' (SEQ ID NO: 50) 5'-AGAGACTCCCACAGCACGCCAGCCAGT-3' (SEQ ID NO: 51) Va1309I1e 5'-GGAACGCAAGGCAGACATCTGATCACTGATAAACAAATC-3' (SEQ ID NO: 52) 5'-GATTTGTTTATCAGTGATCAGATGTCTGCCTTGCGTTCC-3' (SEQ ID NO: 53) Pro322Leu 5'-CAACCAGAGAATCTTAACTCTCAAGATAAACAACTATTTG-3' (SEQ ID NO: 54) 5'-CAAATAGTTGTTTATCTTGAGAGTTAAGATTCTCTGGTTG-3' (SEQ ID NO: 55) Pro694G1n -5'-GGTTGGGATTGGAATAGAATGCAAGGGGCAACCACT-3' (SEQ ID NO: 56) 5'-AGTGGTTGCCCCTTGCATTCTATTCCAATCCCAACC-3' (SEQ ID NO: 57) His50lAla 5'-TGATGGTACAGCATGGCGAGCTGAAGGCAACTATCCGGGCTA-3' (SEQ ID NO: 58) 5'-TAGCCCGGATAGTTGCCTTCAGCTCGCCATGCTGTACCATCA-3' (SEQ ID NO: 59) Tyr508A1a 5'-GGCAACTATCCGGGCGCCTCTTTCCCAGCC-3' (SEQ ID NO: 60) 5'-GGCTGGGAAAGAGGCGCCCGGATAGTTGCC-3' (SEQ ID NO: 61) .Arg560A1a 5'-CCGCTTGCAGGAGCACACCCTTTTAACTCACCTTCG-3' (SEQ ID NO: 62) 5'-CGAAGGTGAGTTAAAAGGGTGTGCTCCTGCAAGCGG-3' (SEQ ID NO: 63) G1u653A1a 5'-CACCAATGTTTGGTCATCTGCAATTTATAACAAAGATAACCGT-3' (SEQ ID NO: 64) 5'-ACGGTTATCTTTGTTATAAATTGCAGATGACCAAACATTGGTG-3' (SEQ ID NO: 65) .Arg500A1a 5'-CCTGATGGTACAGCATGGGCACATGAAGGCAACTATCCGGGC-3' (SEQ ID NO: 66) 5'-GCCCGGATAGTTGCCTTCATGTGCCCATGCTGTACCATCAGG-3' (SEQ ID NO: 67) His501Lys 5'-GGTACAGCATGGCGAAAGGAAGGCAACTATCCGGGC-3' (SEQ ID NO: 68) 5'-GCCCGGATAGTTGCCTTCCTTTCGCCATGCTGTACC-3' (SEQ ID NO: 69) His50IArg 5'-ACAGCATGGCGACGTGAAGGCAACTATCCGGGC-3' (SEQ ID NO: 70) 5'-GCCCGGATAGTTGCCTTCACGTCGCCATGCTGT-3' (SEQ ID NO: 71) Tyr508Phe 5'-AACTATCCGGGCTTCTCTTTCCCAGCC-3' (SEQ ID NO: 72) 5'-GGCTGGGAAAGAGAAGCCCGGATAGTT-3' (SEQ ID NO: 73) G1u653Asp 5'-CAATG'TTTGGTCATCTGATATTTATAACAAAGATAACCGTTATGG-3' (SEQ ID NO: 74) 5'-CCATAACGGTTATCTTTGTTATAAATATCAGATGACGAAACATTG-3' (SEQ ID NO:
75) G1u653G1n 5'-CAATGTTTGGTCATCTCAAATTTATAACAAAGATAACCGTTATGG-3' (SEQ ID NO: 76) 5'-CCATAACGGTTATCTTTGTTATAAATTTGAGATGACCAAACATTG-3' (SEQ ID NO:
77) a Mutation codons are indicated in bold; bases modified in order to create the desired point mutations are underscored.
Recombinant Expressiojz and Proteizz Purification of cABC I azzd Mutants Recombinant cABC I and the site-directed mutants were expressed and purified as previously described [29] and above. The purity of the enzymes was assessed by 4o SDS-polyacrylamide gel electrophoresis using a pre-cast Invitrogen NuPAGE
12% Bis-Tris gel and Simply Blue SafeStain. Protein concentration was measured using the Bio-Rad Laboratories Bradford assay kit.
Capillary Electrophoresis To study the activities and product profiles of the proteins on each substrate (C6S, DS, C4S), digests of 100 ~.g/mI substrate, 50 mM Tris-HCI, 50 rnM sodium acetate, pH 8.0 with 1 ~,g of recombinant cABC I or the site-directed mutants were placed at 37°C for 14 h. The digests were analyzed using capillary electrophoresis as previously described [29, 36].
Ciz~cular Dichroiszn CD spectra were recorded at 25°C on an Aviv 202 CD
spectrophotometer using Quartz cuvettes with optical path length of 0.1 cm. Scans were collected between 300 and 195 nm with a 1.0-nm bandwidth and a scan rate of 1 nm/min. Three scans were averaged for each protein. For melting experiments, spectra were collected at 5°C
intervals from 5°C to 75°C. Recombinantly-expressed proteins were concentrated and buffer-exchanged into 50 mM sodium phosphate, pH 7.5 using Centricon 10 filters (Millipore). All spectra were collected using a protein concentration of 0.2 rng/ml. The buffer contribution was subtracted for all spectra. The signal was normalized to molar ellipticity, 8M, in degrees~cmZ~dmol-1.
Kirzetic Analysis Recombinant proteins were concentrated and buffer exchanged into 50 mM Tris HCl, 50 mM sodium acetate, pH 8Ø In order to evaluate the activity of chondroitinase ABC I and mutants in a semi-high throughput manner, the kinetic analysis was adapted to a 96-well plate format. The studies were performed in a quartz 96-well plate at 37°C
using a Molecular Devices Spectramax 190 (Molecular Devices). The assay was initiated by adding 1.0 ~l of 0.2-6 ~g/~,l (0.2-6.0 ~,g) of enzyme to 249 ~,l of a solution containing different concentrations of galactosaminoglycan substrates (C4S, C6S and DS) in 50 mM Tris-HCI, 50 mM sodium acetate, pH 8Ø Each well contained different substrate concentrations ranging from 0.1 to 5 mg/ml. Product formation was monitored by measuring the absorbance at 232nm every 2-3 seconds. Evaluation of the kinetic data was based on the initial reaction rate.
Docking of CS azzd DS SubstYates in the Active Site of cABC I
3o The SARF2 program was used to determine the C-alpha (CA) atoms in cABC I
and cAC structure that gave an optimal rms deviation upon superimposing the two structures. Superposition of the 452 CA atoms identified by the SARF2 program in the cAC co-crystal structures (with C4S and DS) and the cABC I crystal structure (rmsd of 2.2 ~) provided the initial location and orientation of the CS and DS
substrates relative to the putative active site of cABC I. The coordinates of C4S (GlcA-GalNAc4S)Z
and DS (IdoA-GalNAc4S)Z tetrasaccharides were available from the two cAC co-crystal structures. The initial orientation of both of these substrates had many unfavorable steric contacts which were removed by manually orienting the substrate. In the case of the DS
tetrasaccharide the C5 proton was facing away from the putative active site residues (His501, Tyr508 and Arg560). Thus, this substrate was further re-oriented to ensure that the C5 proton was accessible for abstraction by the active site amino acids.
The manually adjusted orientations of the enzyme-substrate complexes were further optimized using energy minimization. The AMBER force field modified for carbohydrates was further modified to include O-sulfate and sulfamate groups.
This modified AMBER force field was used to assign the potentials for both the enzyme as well as the tetrasaccharide substrates. A subset of the enzyme coordinates around the active site groove was defined to include all of the putative active site amino acids and several additional amino acids that could be involved in the catalytic activity. The enzyme-substrate complex was subject to minimization first without charges and then with charges using 500 steps of steepest descent and 500 steps of conjugate gradient 2o methods. Most of the protein was axed, and only the amino acids that were a part of the active site subset were allowed to move during the minimization. The final rms derivatives of the energies were below 0.1. The ring conformation of the monosaccharides was not distorted by the minimization procedure. The Viewer and Discover modules of InsightII (Release 2000.1, Accelrys, San Diego, CA) were used for the orientation of the substrate and the energy minimization, respectively.
Results Claond~oitiyaase ABC I Claaracterizatiora 3o The gene for cABC I was cloned from Proteus vulgaris genomic DNA without its putative leader sequence. The PCR product was subcloned into pET28a and expressed in Esclzericlaia coli with an N-terminal 6x histidine tag. A series of sequence discrepancies between this clone and the reported protein sequence [35, 37, 38]
necessitated site-directed mutagenesis efforts to make our clone conform to the previously published protein sequence [35]. The catalytic activity of our cloned cABC I
was characterized with various GaIAG substrates (including C4S, C6S and DS) using a semi-high throughput procedure. This procedure enabled us to obtain multiple initial velocity measurements between one substrate-enzyme pair within one minute. Km and Vm~ infozmation could be generated from this data almost immediately. Multiple runs for each enzyme-substrate pair could also be performed in a short period of time to to establish a better confidence in the data generated. The kinetic constants for the activity of cABC I on C6S and DS substrates axe reported in Tables 9 and 10, respectively. For C4S, recombinant cABC I had a Km of 1.5 wM, a k~at of 52000 miri 1 and a catalytic effciency of 35000 NM-1 miri ~. The data suggests robust activity on all three substrates;
however, there is a clear preference for the C4S and C6S substrates. The catalytic 1s efficiency is about 3-fold higher for C4S and C6S compared to DS.
Site-Directed Mutagenesis Studies The cABC I crystal structure [35] revealed 4 conserved amino acids in the putative active site of the enzyme which share high structural homology with 20 corresponding amino acids in cAC that play a role in its catalytic activity [31]. The residues- His501, Tyr508, Arg560, and G1u653 along with Arg500, which was implicated to have a catalytic role based on its crystal structure [35], were mutated to alanine to determine their importance in GalAG degradation. The analyses on these mutants indicated that while Arg500A1a still retained some level of GalAG
degradation 25 activity, the other four mutants were essentially inactive. Based on the results the importance of these residues in the activity of cABC I was established.
A detailed investigation into the roles of these amino acids in the activity of cABC I was performed by generating several additional active site mutants:
His501Arg, His501Lys, Tyr508Phe, G1u653Asp and G1u653G1n. A structural model of the enzyme-3o substrate complex was also constructed to provide a framework for interpreting the results of the mutagenesis experiments. Chondroitinase ABC I mutants were analyzed for their activity against GaIAG substrates by scanning for product formation (as measured via OD232 detection) against C6S and DS. Mutants with detectable activities were further characterized through kinetics assays. Capillary electrophoretic studies allowed for an inspection of an end-point product profile analysis following an exhaustive 14-18 hour digestion with C6S, DS, or C4S as substrate. Circular dichroism data on all mutants were also collected, and a melting curve analysis was performed to ensure that mutagenesis did not compromise the enzyme structurally (Fig. 9).
All His501 mutations (His501A1a, His541Lys, and His501Arg) showed no activity against C6S and DS substrates while scanning for product formation.
Additionally, the His501 mutants did not produce any products in capillary electrophoretic assays, suggesting that His501 is important for cABC I
activity. Though Tyr508A1a proved inactive against C6S and DS while scanning fox product formation and was unable to degrade C6S, DS, and C4S in exhaustive digestions, Tyr508Phe was able to pxocess GaIAG substrates. In an exhaustive digestion, product profile analysis revealed electropheretograms virtually indistinguishable from those produced with recombinant cABC I. Tyr508Phe processes C6S (Fig.10) with both diminished binding (Km of 36.4 ~M compared with 1.2 N.M for recombinant cABC I) and markedly reduced turnover number (k~at of 31.2 miri 1 compared with 37362 miri I for recombinant cABC
I). Tyr508Phe acts on DS in a similar fashion (Fig. 10) with a Km of 48.9 E.~M
and a k~ar of 104.8 miri 1 (compared with a I~,=, of 2.5 ~M and a k~at of 27102 miri I
for recombinant cABC I). Therefore, the tyrosine to phenylalanine mutation results in an enzyme with a much higher Km and a greatly reduced k~at suggesting that this residue possibly plays an important role in substrate positioning and turnover. Unlike His501, the Tyr508Phe mutant does not seem to affect a critical step in GaIAG degradation since it still produces products in an end-point analysis (whereas the His501 mutants were inactive).
Based on these results, His501 is most likely the residue involved in proton abstraction from the C-5 position of the uronic acid, which is an important step in the GalAG
degradation process.
The other mutants were active against both C6S and DS, though with far less 3o processing efficiency than recombinant cABC I. The GIu653 analog in cAC
(G1u371) was believed to play a role in positioning adjacent histidine and arginine residues through hydrogen bonding [31]. In cABC I, G1u653 was investigated by decreasing the effective protrusion of the glutamic acid into the active site by mutating it to an aspartic acid and also by a slight perturbation of the hydrogen bonding network by mutation to a glutamine residue. Although the G1u653Asp mutant proved to be catalytically inactive against both C6S and DS in kinetics assays, ors overnight digestion this mutant was able to produce products on these substrates as well as on C4S. G1u653G1n maintained some level of activity against both C6S and DS, with a slight increase in Km for both substrates and a greater than 20-fold reduction in lc~at for C6S and a 5-fold reduction in k~at for DS
(Fig. 11). The data suggest that while this residue does not play a major role in substrate positioning, its major role is probably in affecting the catalytic turnover of the enzyme.
Against C6S, Arg500A1a remained active, but with a 17-fold increase in Km and a 1500-fold reduction in catalytic efficiency. With DS' Arg500A1a showed similar losses, with a .
14-fold increase in Km and a greater than 2000-fold decrease in catalytic efficiency. To study the results of the kinetic analyses of the mutants in the context of the structure of the enzyme, theoretical models of the enzyme-substrate structural complexes were constructed.
Enzyme-Substrate Stz~zcctu~al Corzzplex - Putative Roles fo>" Active Site Arniyzo Acids The structure of cABC I contains three domains viz. an N-terminal (3-domain with a jellyroll fold, the catalytic oc-helix domain [incomplete toroid (ala)5 fold] and a C-terminal antiparallel a sheet domain. The structural fold of cABC I, comprising the catalytic a-helix domain and the C-terminal j3-sheet domain is very similar to that of cAC and bacterial hyaluronate lyases. To obtain a clearer picture of the active site and positioning of the substrate within cABC I, its structure was superimposed on the co-crystal structures of the structurally related cA_C and hyaluronate lyase (HAL). The CA
atoms chosen for superimposition were obtained from the SARF2 program. This superimposition aligned most of the C-terminal (3-sheet domains. However, the oc-helix domain did not align very well, since the cleft formed by the N-terminal and C-terminal regions of this domain was more open in cA_BC I as compared to the closed grooves 3o found in cAC and HAL. Based on the contacts with the substrate and their equivalent amino acids (shown in parentheses) implicated in cAC activity, the amino acids His501 (His225), Tyr508 (Tyr234), Arg560 (Arg288) and G1u653 (GIu371) were proposed to be involved in the catalytic activity of cABC I.
In the case of cAC, co-crystal structures with DS and chondroitin sulfates have been solved [31, 39]. Thus, the superimposition of these co-crystal structures with cABC I provided a guiding framework for modeling the enzyme-substrate structural complex. The orientation of both chondroitin and dermatan sulfate substrates in the cAC
co-crystal structures are identical, despite the structural differences between these substrates. The closed nature of the active site groove and the parallel pyranose ring stacking interactions with the substrate provided by the bulky aromatic groups of Trp127 l0 and Trp427 on the opposite faces of the groove act as constraints that fix the orientation of the substrate in the active site. In the case of cABC I, the active site groove is more open, and there are no tryptophan amino acids to provide a Iarge steric hindrance to the positioning of the substrates in the active site. These structural differences in the active site of cAC and cABC I account for the broader substrate specificity of cABC I
(Fig.
1s 12). The interactions of the active site amino acids of cABC I with C4S and DS
substrate are discussed below.
Interactio~as with C4S Substrate The position and orientation of C4S relative to the active site of cABC I was 2o similar to that of the cAC co-crystal structure with the C4S substrate (Fig. 13). From the proximity of the amino acids towards the CS proton of GlcA in the +1 subsite, His501 is positioned more favorably to abstract this proton compared to Tyr508. The close proximity between the glycosidic oxygen of the -l, +1 glycosidic bond and Tyr508 suggests that it may play a role in protonating the leaving group. Arg560 is also 25 proximal to the glycosidic oxygen of the scissile bond and its equivalent cAC Arg288 has been implicated to play a role in protonation of the leaving group [31].
However, the Arg288A1a mutant in cAC did not completely abolish its activity [31]. G1u653 does not seem to be involved directly in the catalysis, but it is at hydrogen bonding distance with His501 and Arg560 and thus likely plays a role in positioning these residues for 30 catalysis. The hydrogen bonding interaction of the analogous cAC GIu371 with the corresponding histidine and arginine residues has been observed in cAC and a similar role for G1u371 has been proposed. Another important step in the (3-eliminative cleavage of lyases is the neutralization of the charge on the carboxyl group of the uronic acid to facilitate the abstraction of the proton. Based on our structural complex, Arg500 is positioned to interact with the carboxylate group of the uronic acid at the +1 subsite. The stabilization of the carbanion intermediate could be achieved by potential interactions of either the protonated base His501 or Arg500 or Arg560, since all of these groups are positioned to interact with the CS carbanion on the uronic acid formed after abstraction of the oc-proton.
Iyzteractioras with DS Substrate The initial positioning of the DS substrate based on its relative orientation in the cAC active site was such that the CS proton of the IdoA in the +1 subsite was facing away from the putative catalytic amino acids. In the cAC active site, the DS
substrate is locked in this orientation due to the structural constraints imposed by the more closed active site groove and the two tryptophan amino acids. These observations are consistent with the inability of cAC to cleave DS. Rather, it has been observed that DS
binds to the active site of cAC and inhibits its activity toward chondroitin substrates.
The chemical differences between IdoA in dermatan sulfate and GIcA in C4S
provide further insights into differences in positioning of these substrates within the 2o active site. While in GIcA the CS proton and the glycosid>ic oxygen of the cleavable bond are in the cis orientation, in IdoA these two atoms are in the tiaras orientation.
Since the active site amino acids involved in the proton abstraction (from CS
of uronic acid) and donation (to the glycosidic oxygen of the cleaved bond) are on the same face of the active site groove, the DS substrate would need to re-orient in order for these amino acids to cleave it. Thus, there are salient differences between the mechanism governing DS cleavage and the mechanism cABC I employs for C4S degradation.
A theoretical cABC I-DS complex was constructed by docking the substrate such that the CS proton faces the active site amino acids. Based on the model, His501 is the best candidate to serve as the general base that abstracts the CS proton from the IdoA in 3o the +1 subsite (Fig. 14). The positioning of the CS proton such that it would be abstracted by His501 results in the carboxylate group of the IdoA being proximal to Arg560. Thus, Arg560 could play a role in neutralizing the charge on this group to make the CS proton more labile (Fig. 14). It is possible that the dermatan substrate reorients itself aftex proton abstraction for the lone pairs of the glycosidic oxygen to face the active site Tyr508 or Arg560. The fact that Arg560 and Arg500 are on opposing sides of the substrate provide further flexibility far interaction with substrate during the proton abstraction and donation processes (Fig. 14).
Irnplicatioras fog tlae Mode ofActioyz of cABCI
The results from the site-directed mutagenesis of the active site amino acids are 1o consistent with observations from the theoretical enzyme-substrate structural complex.
Coupled analysis of both the kinetics experiments and the investigations of product profiles by capillary electrophoresis strongly support the notion that His501 is important for the activity of cABC I on C6S, DS, and C4S. Indeed, no products were observed in any reaction involving any of these substrates with any of the His50I mutants.
From this, it appears that His501 plays a central role in catalysis- the abstraction of the C5 proton from the uronic acid moiety. The proximity of Tyr508 to the C5 proton and the glycosidic oxygen in the cABC I-chondroitin structural complex suggested its potential role in protonating the leaving group. However, the Tyr508Phe mutant did produce products against both C6S and DS in the overnight digestion. This mutant retains the 2o hydrophobic group of tyrosine but abolishes the proton donating hydroxyl group. Thus the role of Tyr508 in proton donation is less conclusive, and it can potentially be compensated for by water molecules in the active site, albeit at reduced catalytic efficiency consistent with the kinetics data. The aromatic ring of Tyr508 likely plays a role in the positioning of substrate.
Since the G1u653A1a mutant proved to be inactive against C6S, DS, and C4S, this residue is important for activity. The crystal structure of cABC I and the enzyme-substrate model reveal that GIu653 forms an hydrogen bonding network with Arg560 and His501, thus positioning these amino acids for catalysis. This role is confirnned by the product formation (in the overnight digestion) of the G1u653Asp and G1u653G1n 3o mutants. Indeed, the relatively unchanged Km between cABC I and GIu653GIn for both C6S (Table 9) and DS (Table 10) suggests that this residue is not important for directly binding substrate. Further, the diminished protrusion of the aspartic acid hydrogen bonding sidechain as compared with the glutamic acid and glutamine sidechains is consistent with the relative order of activities (Fig. 11). Chondraitinase ABC
I, with its glutamic acid at position 653, has the mast effective hydrogen bonding network with which to position its catalytic neighbors, Arg560 and His501; G1u653A1a contains no hydrogen bonding capability at all. G1u653G1n has a more effective hydrogen bonding network than does G1u653Asp, which has shorter sidechain length and thus is not in close enough proximity to act effectively.
to Table 9: Kinetic Analysis of cABC I and Mutants with C6S as Substrate a Enzyme Km Kcat Kcat~ Km ~.M miri 1 ~.M-~ miri Chondroitinase ABC 1.2 ~ 0.6 37000 ~ 6500 31000 I

His501A1a or Lys or nab no no Arg Tyr508A1a no no no 2o Tyr508Phe 36.4 31.2 0.9 Arg560A1a no no no G1u653A1a or Asp no no no G1u653G1n 6.1 1607.6 262.1 Arg500A1a 19.9 418.6 21.0 a Values are the experiments ~
mean of at least standard deviation.
three b no, not available.

Table 10: Kinetic Analysis of cABC I and Mutants with DS as Substrate EriZyrile Km Kcat Kcat~ Km ECM miri 1 N.M-1 miri Chondroitinase ABC 2.5 ~ 0.5 27000 ~ 2500 11000 I

His501A1a or Lys or nab no no Arg Tyr508A1a no no no Tyr508Phe 48.9 104.8 2.11 4o Arg560A1a no ria no G1u653A1a or Asp no no no G1u653G1n 4.16 5174.8 1245 Arg500A1a 35.68 162.0 4.54 a Values are the mean of at least three experiments ~ standard deviation.
b na, not available.
Arg560A1a produces no products of C6S or C4S and negligible products of DS
by CE analysis. The proximity of Arg560 to the C5 atom and the glycosidic oxygen suggests that it plays a role in proton donation and/or stabilization of the carbanion intermediate following proton abstraction. It ~is likely to play the latter role since proton donation can be compensated via neighboring water molecules, and further, the Tyr508 is better positioned to protonate the leaving group based on the model. Arg560 could play an additional role in neutralizing the carboxylate of the IdoA in DS
based on its proximity to this group in the modeled c~BC I-dermatan structural complex. The structural model of the cABC I-chondrotin complex and the earlier crystal structure studies [3I, 35] suggest that Arg500 is likely to neutralize the charge on the carboxylate group of GlcA in CS. However, the Arg500A1a mutant does not conclusively support this role since this mutant retains its ac-~ivity towards chondroitin and dermatan substrates.
In addition to the catalytic amino acids already described, the cABC I active site contains several other basic residues. While some of these have st1-uctural analogs in the cAC and HAL co-crystal structures, there ara many others which are unique to cABC I.
The highly basic nature of the active site could be involved in accommodating a wide variety of substrates including C4S, C6S, DS and HA which have different charge distributions due to their differences in sulfation pattern. His561 and Asn564 are positioned to interact with the 4-O sulfate group of the GalNAc4S at the -1 subsite (present in both C4S and DS). Furthermore, several additional basic amino acids, including His388, Arg395, Arg105, Lys312~ are located on the upper side of the active site cleft towards the N-terminal (3-sheet domain (Fig. 12). These basic amino acids could play a role in governing the specificity of cABC I towards different substrates.
Discussion There is accumulating evidence that implicate GaIAGs in numerous biological processes ranging from cell growth and development to anticoagulation and microbial pathogenesis. Biochemical characterization of chondroitinases [GaIAG
depolymerizing enzymes] in terms of their catalytic mechanism and substrate speci~cities is important for the development of enzymatic tools for decoding structure-function relationships of GaIAGs. The biochemical characterization of heparinases has been quite successful in developing these enzymes into valuable tools for the sequencing of HSGAGs [27]
and in directly probing the biological roles of HSGAGs, such as in cancer [40]. Of the various chondroitinases, cABC is the enzyme with the broadest substrate specificity in terms of l0 cleaving chondroitin and dermatan sulfates. Engineering cABC enzymes via site-directed mutagenesis provides a repertoire of mutants with fine-tuned substrate specificities. These mutants not only facilitate the structural characterization of GaIAGs, but they can also be directly utilized in physiological scenarios such as nerve regeneration after spinal cord injury, thus expanding the scope of treatment strategies.
While the broad substrate specificity of cABC offers the ability to engineer novel mutants of this enzyme with defined specificities, it has made it challenging to characterize the structure-function relationship of the enzyme.
GaIAG lyases are believed to cleave substrate through a stepwise [i-elimination mechanism [41]. The fundamental steps involved in this mechanism are proton 2o acceptance and donation [42]. First, the substrate binds to the catalytic cleft of the enzyme and the carboxyl group on the C-5 carbon of the uronic acid moiety is neutralized. The next three features of the reaction are central: (1) the abstraction of the C-5 proton on the uronic acid moiety, causing the formation of a double bond between C-4 and C-5, (2) the stabilization of the carbanion intermediate, and (3) the protonation of the anomeric oxygen, breaking the glycosidic bond. Finally, the cleaved disaccharide is released from the active site and the catalytic residues balance protons via exchange with water.
The wealth of crystal structures of chondroitinase AC and B with different substrates and reaction products have provided structural insights into the roles of active 3o site amino acids in governing the substrate specificity and catalytic mechanism [30, 31].
In the studies presented herein cABC I from P.vulgaris was cloned and recombinantly expressed, and a kinetic analysis of each of these residues mutated to alanine was conducted.
The studies presented provide the identification and defining of the roles of the active site amino acids in substrate recognition, positioning, and processing functions of the enzyme. By coupling kinetic analysis of site-directed mutants of the active site amino acids with the construction of theoretical enzyme-substrate structural complexes to interpret the effects of the mutants, the detailed roles of the 4 active site amino acids have been outlined.. His501 is an important residue, as its mutants (Ala, Lys, Arg) proved null against all GaIAG substrates. This residue is Zikely involved in proton to abstraction from the uronic acid moiety of the GaIAG. Though the studies with Tyr508AIa proved consistent with its acting as a general base, the Tyr508Phe mutant diminished the likelihood of this function. Tyr508Phe gener~.ted products on overnight digestion with all GalAG substrates, making it unlikely that this residue modulates such a central role in catalysis. The results suggest that Tyr508 plays a role in the positioning of substrate via hydrogen bonding with the glycosidic bond of the GaIAG.
Similarly, the role of G1u653 with other catalytic residues via hydrogen bonding is confirmed by the mutagenesis studies presented herein. Arg560 seems to play a part in cABC I's activity, perhaps in stabilizing the enolate intermediate through its positive charge.
It also may act as the general acid in the reaction.
2o Mutagenesis of Arg500 was also performed, since it was previously suggested that Arg500 would be able to interact with the carboxylate group of either epimer of uronic acid, thus enabling cABC I's most remarkable ability ~o process both CS
and DS
[35]. Through its sidechain flexibility, Arg500's guanidiniurn group was thought to aid in charge neutralization of either uronic acid configuration. However, the results indicate that Arg500 is not crucial for the processing of GalAG substrates, since the Arg500A1a mutant did generate products in both product pxofile studies and kinetics assays. It may be that a number of residues are important in this charge neutralization process.
Based on the enzyme-substrate structural complexes insights into the differences 3o in processing of chondroitin and dermatan sulfate by cABC I were obtained.
The structural models suggest that the catalytic residues in cABC I are positioned to cleave chondroitin substrates more favorably than dermatan substrates. This is consistent with the kinetics of the wild-type enzyme which shov~rs better catalytic efficiency towards chondroitin versus dermatan substrates. The enzyme-substrate structural models also revealed several other amino acids in the active site that likely play a role in substrate . positioning and specificity.
References for Example 2 1 Ernst, S., Langer, R., Gooney, C. L. and Sasisekharan, R. (1995) Enzymatic l0 degradation of glycosaminoglycans. Grit Rev Biochem Mol Biol 30, 387-444 2 Nadanaka, S. and Sugahara, K. (1997) The unusual tetrasaccharide sequence GIcA beta 1-3GalNAc(4-sulfate)beta 1-4GlcA(2-sulfate)beta 1-3GalNAc(6-sulfate) found in the hexasaccharides prepared by testicular hyaluronidase digestion of shark cartilage chondroitin sulfate D. Glycobiology 7, 253-263 3 Sugahara, K., Tanaka, Y., Yamada, S., Sano, N., Kitagawa, H., Haslam, S. M., Morns, H. R. and Dell, A. (1996) Novel sulfated oligosaccharides containing 3-O-sulfated glucuronic acid from king crab cartilage chondroitin sulfate K.
Unexpected degradation by chondroitinase ABC. J Biol Chem 271, 26745-26754 4 Trowbridge, J. M. and Gallo, R. L. (2002 Dermatan sulfate: new functions from 2o an old glycosaminoglycan. Glycobiology 12, 1178-1258 5 Sugahara, K., Mikami, T., Uyama, T., Mizuguchi, S., Nomura, K. and Kitagawa, H. (2003) Recent advances in the structural biology of chondroitin sulfate and dermatan sulfate. Curr Opin Struct Biol 13 , 612-620 6 Liaw, P. C., Austin, R. C., Fredenburgh, J. C., Stafford, A. R. and Weitz, J. I.
(1999) Comparison of heparin- and dermatan sulfate-mediated catalysis of thrombin inactivation by heparin cofactor II. J Biol Chem 274, 27597-27604 7 Fernandez, J. A., Petaja, J. and Griffin, J. H. (1999) Dermatan sulfate and LMW
heparin enhance the anticoagulant action of activated protein C. Thromb Haemost 82, 1462-1468 8 Iozzo, R. V. (1997) The family of the small leucine-rich proteoglycans: key regulators of matrix assembly and cellular growth. Crit Rev Biochem MoI Biol 32, 141-174 9 Tumova, S., Woods, A. and Couchman, J. R. (2000) Heparan sulfate chains from glypican and syndecans bind the Hep II domain of fibronectin similarly despite minor structuxal differences. J Biol Chem 275, 9410-9417 Schmidt, G., Robenek, H., Harrach, B., Glossl, J., Nolte, V., Hormann, H., Richter, H. and Kresse, H. (1987) Interaction of small dermatan sulfate proteoglycan from fibroblasts with fibronectin. J Cell Biol 104, 1683-1691 I 0 11 Walker, A. and Gallagher, J. T. ( 1996) Structural domains of heparan sulphate for specific recognition of the C-terminal heparin-binding domain of human plasma fibronectin (HEPII). Biochem J 317 ( Pt 3), 871-877 12 Elefteriou, F., Exposito, J. Y., Garrone, R. and Lethias, C. (2001) Binding of tenascin-X to decorin. FEBS Lett 495, 44-47 is 13 Yamaguchi, Y., Mann, D. M. and Ruoslahti, E. (1990) Negative regulation of transforming growth factor-beta by the proteoglycan decorin. Nature 346, 281-14 Hildebrand, A., Romans, M., Rasmussen, L. M., Heinegard, D., Twardzik, D.
R., Border, W. A. and Ruoslahti, E. (I994) Interaction of the small interstitial proteoglycans biglycan, decorin and fibromodulin with transforming growth factor beta. Biochem J 302 ( Pt 2), 527-534 15 Lyon, M., Deakin, J. A., Mizuno, K., Nakamuxa, T. and Gallagher, J. T.
(1994) Interaction of hepatocyte growth factor With heparan sulfate. Elucidation of the major heparan sulfate structural determinants. J Biol Chem 269, 11216-11223 16 Lyon, M., Deakin, J. A., Rahmoune, H., Fernig, D. G., Nakamura, T. and Gallagher, J. T. (1998) Hepatocyte growth factor/scatter factor binds with high affinity to dermatan sulfate. J Biol Chem 273, 271-278 17 Mascellani, G., Liverani, L., Bianchini, P., Parma, B., Toxri, G., Bisio, A., Guerrini, M. and Casu, B. (1993) Structure and contribution to the heparin 3o cofactor II-mediated inhibition of thrombin of naturally oversulphated sequences of dermatan sulphate. Biochem J 296 ( Pt 3), 639-648 18 Maimone, M. M. and Tollefsen, D. M. (1991) Structure of a dermatan sulfate hexasaccharide that binds to heparin cofactor II with high affinity. J Biol Chem 266, 14830 19 Denholrn, E. M., Lin, Y. Q. and Silver, P. J. (2001) Anti-tumor activities of chondxoitinase AC and chondroitinase B: inhibition of angiogenesis, proliferation and invasion. Eur J Pharmacol 416, 213-221 20 Iozzo, R. V. and Cohen, I. (1993) Altered proteoglycan gene expression and the tumor strorna. Experientia 49, 447-455 21 Makatsori, E., Lamari, F. N., Theocharis, A. D., Anagnostides, S., Hjerpe, A., to Tsegenidis, T. and Karamanos, N. K. (2003) Large matrix proteoglycans, versican and perlecan, are expressed and secreted by human leukemic monocytes.
Anticancer Res 23, 3303-3309 22 Papadas, T. A., Stylianou, M., Mastronilcolis, N. S., Papageoxgakopoulou, N., Skandalis, S., Goumas, P., Theocharis, D. A. and Vynios, D. H. (2002) Alterations in the content and composition of glycosaminoglycans in human laryngeal carcinoma. Acta Otolaryngol 122, 330-337 23 Vicente, C. P., Zancan, P., Peixoto, L. L., Alves-Sa, R., Axaujo, F. S., Mourao, P.
A. and Pavao, M. S. (2001) Unbalanced effects of dermatan sulfates with different sulfation patterns on coagulation, thrombosis and bleeding. Thromb 2o Haemost 86, 1215-1220

24 Gandra, M., Cavalcante, M. and Pavao, M. (2000) Anticoagulant sulfated glycosaminoglycans in the tissues of the primitive chordate StyeIa plicata (Tunicata). Glycobiology 10, 1333-1340 Rhomberg, A. J., Ernst, S., Sasisekharan, R. and Biemann, K. (1998) Mass

25 spectrometric and capillary electrophoretic investigation of the enzymatic degradation of heparin-like glycosaminoglycans. Proc Natl Acad Sci U S A 95,

26 Guerrini, M., Raman, R., Venkataraman, G., Torri, G., Sasisekharan, R. and Casu, B. (2002) A novel computational approach to integrate NMR spectroscopy 3o and capillary electrophoresis for structure assignment of heparin and heparan sulfate oligosacchaxides. Glycobiology 12, 713-719

27 Venkataraman, G., Shriver, Z., Raman, R. and Sasisekharan, R. (1999) Sequencing complex polysaccharides. Science 286, 537-542

28 Ernst, S., Rhomberg, A. J., Biemann, K. and Sasisekharan, R. (I998) Direct evidence for a predominantly exolytic processive mechanism for depolymerization of heparin-like glycosaminoglycans by heparinase I. Proc Natl Acad Sci U S A 95, 4182-4187

29 Pojasek, K., Shriver, Z., Kiley, P., Venkataraman, G. and Sasisekharan, R.
(2001) Recombinant expression, purification, and kinetic characterization of chondroitinase AC and chondroitinase B from Flavobacterium heparinum.
1o Biochem Biophys Res Commun 286, 343-351

30 Huang, W., Matte, A., Li, Y., Kim, Y. S., Linhardt, R. J., Su, H. and Cygler, M.
( 1999) Crystal structure of chondroitinase B from Flavobacterium heparinum and its complex with a disaccharide product at 1.7 A resolution. 3 Mol Biol 294,

31 Huang, W., Boju, L., Tkalec, L., Su, H., Yang, H. O., Gunay, N. S., Linhardt, R.
J., Kim, Y. S., Matte, A. and Cygler, M. (2001) Active site of chondroitin AC
lyase revealed by the structure of enzyme-oligosaccharide complexes and mutagenesis. Biochemistry 40, 2359-2372

32 Michel, G., Pojasek, K., Li, Y., Sulea, T., Linhardt, R. J., Raman, R., Prabhakar, V., Sasisekharan, R. and Cygler, M. (2004) The structure of chondroitin B
lyase complexed with glycosaminoglycan oligosaccharides unravels a calcium dependent catalytic machinery. J Biol Chem 279, 32882-32896 34 Bradbury, E. J., Moon, L. D., Popat, R. J., King, V. R., Bennett, G. S., Patel, P.
N., Fawcett, J. W. and McMahon, S. B. (2002) Chondroitinase ABC promotes functional recovery after spinal cord injury. Nature 416, 636-640 Huang, W., Lunin, V. V., Li, Y., Suzuki, S., Sugiura, N., Miyazono, H. and Cygler, M. (2003) Crystal structure of Proteus vulgaris chondroitin sulfate ABC
lyase I at 1.9A resolution. J Mol Biol 328, 623-634 36 Pojasek, K., Rarnan, R., Kiley, P., Venkataraman, G. and Sasisekharan, R.
(2002) 3o Biochemical characterization of the chondroitinase B active site. J Biol Chem 277, 31179-31186 37 Hamai, A., Hashimoto, N., Mochizuki, H., Kato, F., Makiguchi, Y., Horie, K.
and Suzuki, S. (1997) Two distinct chondroitin sulfate ABC lyases. An endoeliminase yielding tetrasaccharides and an exoeliminase preferentially acting on oligosaccharides. J Biol Chem 272, 9123-9130 38 Sato, N., Shimada, M., Nakajima, H., Oda, H. and Kimura, S. (1994) Cloning and expression in Escherichia coli of the gene encoding the Proteus vulgaris chondroitin ABC lyase. Appl Microbiol Biotechnol 41, 39-46 39 Lunin, V. V., Li, Y., Linhardt, R. J., Miyazono, H., Kyogashima, M., Kaneko, T., Bell, A. W. and Cygler, M. (2004) High-resolution crystal structure of 1o Arthrobacter aurescens chondroitin AC lyase: an enzyme-substrate complex defines the catalytic mechanism. J Mol Biol 337, 367-386 40 Liu, D., Shriver, Z., Venkataraman, G., El Shabrawi, Y. and Sasisekharan, R.
(2002) Tumor cell surface heparan sulfate as cryptic promoters or inhibitors of tumor growth and metastasis. Proc Natl Acad Sci U S A 99, 568-573 41 Gerlt, J. A. and Gassman, P. G. (1993) Understanding the rates of certain enzyme-catalyzed reactions: proton abstraction from carbon acids, acyl-transfer reactions, and displacement reactions of phosphodiesters. Biochemistry 32, 42 Jedxzejas, M. J. (2000) Structural and functional comparison of polysaccharide-degrading enzymes. Crit Rev Biochem Mol Biol 35, 221-251 Example 3 Materials and Methods Deternainatio~a ofEffect ofDivale~ats on Recorrabinarat cABCI activity For these studies, C6S and DS were dissolved at a I mg/nnL, concentration in mM Tris pH 8.0 (no salt) containing a fixed concentration (lOmM) of different divalent 3o ion salts (Ca2+, Mga+, Mn2+, Znz+). Recombinant cABC I (0.2 ~,g} was added to each of these solutions, and the activity of the enzyme was assessed based on the change in absorbance at 232 nm (A23a ~ minute). These experiments were carried out on a SpectraMax 190 (Molecular Devices) using a 96 well quartz plate. The temperature was set at 37 °C for these experiments, and enzyme activity was calculated based on the initial rate of product formation.
Results Table 11 provides an activity summary of wildtype cABCl and cABC 1 mutants.
l0 Table ll:Activity Summary of cABC I WiIdtype and Mutants Capillary Enzyme Electrophoresis WILDTYPE + + +

H8f71 A

R560A ~ - mod ,.,...~..,.~_._~~?BA....,..,..,, ~......,.~.._. ..._~,.,~,~_.a.,.
_. .... ,~".w ...

R500A + partial +

H388A + ~ +

H389A + _ +

H5~9 K : .

H5~9 R
.,.. : ~ ..: _.:... _..
, _......~_ - .

. + + +
.
. Y508F

R560K , + _ .

E653D + low E653Q + + +

H388K + -H389K + + +

H388R . +

H389R + - +

Fig. 26 provides a schematic depicting the calcium coordination motif. The effect of different divalents on the activity of cABC I on chondroitin-6-sulfate and dermatan sulfate was assessed. With C6S as the substrate there was no apparent change in enzyme activity upon addition of calcium, magnesium or manganese. The addition of zinc appeared to have an inhibitory effect as reported previously.
Interestingly, the activity of cABC I on dermatan sulfate increased drastically in the presence of added calcium and magnesium, when compared to the control (1 mg/mL DS in 50 mM Tris pH
8.0). The presence of zinc was again found to be inhibitory.
In order to further understand the role of calcium in the selective enhancement of cABC I activity towards DS, the calcium concentration at which maximal activity was observed was evaluated. For these calcium titration experiments the same experimental set-up was used and the concentration of added CaCl2 was varied from 0 - 20 mM. The data clearly indicated that maximum activity was obtained at 10 mM CaClz.
It is important to note that the initial experiments with added calcium were done in the absence of any additional salt in the buffer; therefore, it was ascertained that the to enhancement observed for DS processing is not just due to a salt effect. To address this a comparison of the activity of the enzyme on DS in presence of an optimal amount of sodium acetate and varying the calcium concentration was performed. Dermatan sulfate at a 1 mg/mL concentration was dissolved in 50 mM Tris pH 8.0 buffer containing 25 mM, 50 mM or 100 mM sodium acetate. Using each of these as starting solutions the calcium titration experiment was repeated by adding various amounts of CaClz (0 - 20 mM). Fig. 27 shows that the rate enhancement observed upon the addition of 10 mM
CaCl2 still exceeds that observed when using the optimum salt concentration (100 mM
sodium acetate). The results also indicate that the maximum enhancement observed is constant at 10 mM calcium irrespective of the sodium acetate content in the starting 2o buffer. This is probably an indication that the effect of calcium is independent from a salt effect.
Based on these observations a kinetic analysis of cABC I processing on DS in the presence and absence of 10 mM CaCl2 was also performed. The kinetic parameters of cABC I with and without calcium were as follows:
with 10 mM calcium chloride I~m=3.53 mM
kcat = 33183.91 miri I
without calcium I~m = 1.42 mM
3o kcat = 17237.07 miri 1 Four asparlic acid residues were probed as players in a potential calcium coordination motif. D439 (likely played the part of a "control" for the studies). D442, D444, and D490 were individually mutated to alanine. The results of an activity study are provided below in Table 12.
Table 12: MOJO Calcium Coordination Mutants: Activity Assessments (units are raw readouts) (0.2 fig)(5.0 fig)(5.0 (5.0 (5.0 fig) fig) fig) 1 mglml DS 458 4126 115.5 -2.07 23 50 mM NaAC

1 mg/ml DS

50 mM NaAC 768 3661 86.5 0.79 19 mM Calcium 1 mg/ml DS

50 mM NaAC 365 3162 127 -5.7 59 10 mM Calcium 10 mM EDTA

Although the invention has been described in detail for the purpose of illustration, l0 it is understood that such detail is solely for that purpose and variations can be made by those skilled in the art without departing from the spirit and scope of the invention which is defined by the following claims.
The contents of all references, patents and published patent applications cited throughout this application are incorporated herein by reference.
We claim:

DEMANDES OU BREVETS VOLUMINEUX
LA PRESENTE PARTIE DE CETTE DEMANDE OU CE BREVETS
COMPRI~:ND PLUS D'UN TOME.
CECI EST L,E TOME 1 DE 2 NOTE: Pour les tomes additionels, veillez contacter 1e Bureau Canadien des Brevets.
JUMBO APPLICATIONS / PATENTS
THIS SECTION OF THE APPLICATION / PATENT CONTAINS MORE
THAN ONE VOLUME.

NOTE: For additional valumes please contact the Canadian Patent Office.

Claims

1. A modified chondroitinase ABC I comprising:
the amino acid sequence of a native chondroitinase ABC I, wherein at least one residue at position 105, 131, 154, 218, 219, 221, 222, 253, 276, 286, 309, 312, 322, 388, 389, 392, 439, 442, 444, 490, 500, 501, 508, 560, 561, 587, 653, 678, 694 or 712 has been substituted with a different amino acid than in the native chondroitinase ABC I, and wherein the amino acid sequence of the modified chondroitinase ABC I is not the amino acid sequence of any of SEQ ID NOs: 3-24.

2. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 154 and has been substituted with alanine.

3. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 309 and has been substituted with isoleucine.

4. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 322 and has been substituted with leucine.

5. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 388 and has been substituted with alanine, lysine or arginine.

6. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 389 and has been substituted with alanine, lysine or arginine.

7. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 439 and has been substituted with alanine.

8. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 442 and has been substituted with alanine.

9. The modified chondroitinase ABC I of claim l, wherein the substituted residue is at position 444 and has been substituted with alanine.

10. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 490 and has been substituted with alanine.

11. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 493 and has been substituted with alanine.

12. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 500 and has been substituted with alanine, cysteine or glutamine.

13. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 501 and has been substituted with alanine, lysine or arginine.

14. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 508 and has been substituted with phenylalanine.

15. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 560 and has been substituted with alanine or lysine.

16. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 561 and has been substituted with alanine.

17. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 653 and has been substituted with alanine, aspartic acid or glutamine.

18. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 694 and has been substituted with proline or glutamine.

19. The modified chondroitinase ABC I of claim 1, wherein the substituted residue is at position 712 and has been substituted with alanine.

20. The modified chondroitinase ABC I of claim 1, wherein the substituted amino acid is a conservative amino acid substitution.

21. The modified chondroitinase ABC I of claim 1, wherein the chondroitinase ABC I is a substantially purified recombinant form.

22. A modified chondroitinase ABC I comprising:
the amino acid sequence of the peptide of a native chondroitinase ABC I, wherein the amino acid sequence contains a) at least one residue at position 105, 131, 154, 218, 219, 221, 222, 253, 276, 286, 309, 312, 322, 388, 389, 392, 439, 442, 444, 490, 500, 501, 508, 560, 561, 587, 653, 678, 694 or 712 of the native chondroitinase ABC I and b} at least one amino acid substitution, and wherein the amino acid sequence of the modified chondroitinase ABC I is not the amino acid sequence of any of SEQ ID NOs: 3-24.

23. The modified chondroitinase ABC I of claim 22, wherein the amino acid sequence contains the residue at position 501, 508, 560 or 653 of the native chondroitinase ABC I.

24. The modified chondroitinase ABC I of claim 22, wherein the amino acid sequence contains the residues at position 501, 508, 560 and 653 of the native chondroitinase ABC I.

25. The modified chondroitinase ABC I of claim 22, wherein the substituted amino acid is a substitution of at least one residue at position 105, 131, 154, 218, 219, 221, 222, 253, 276, 286, 309, 312, 322, 388, 389, 392, 439, 442, 444, 490, 500, 501, 508, 560, 561, 587, 653, 678, 694 or 712, wherein the residue is subsituted with a different amino acid than in the native chondroitinase ABC I.

26. The modified chondroitinase ABC I of claim 22, wherein the substituted amino acid is a conservative amino acid substitution.

27. The modified chondroitinase ABC I of claim 22, wherein the chondroitinase ABC I is a substantially purified recombinant form.

28. A modified chondroitinase ABC I having a modified product profile, wherein the modified product profile of the modified chondroitinase ABC I is at least 10% different than a native product profile of a native chondroitinase ABC I, and wherein the amino acid sequence of the modified chondroitinase ABC I is not the amino acid sequence of any of SEQ ID NOs: 3-24.

29. The modified chondroitinase ABC I of claim 28, wherein the modified chondroitinase ABC I has a modified product profile that is at least 20%
different than a native product profile of a native chondroitinase ABC I.

30. The modified chondroitinase ABC I of claim 29, wherein the modified chondroitinase ABC I has a modified product profile that is at least 50%
different than a native product profile of a native chondroitinase ABC I.

31. A modified chondroitinase ABC I having a k cat or K M value for a substrate that is at least 10% different than a native chondroitinase ABC I K cat or K M
value, wherein the amino acid sequence of the modified chondroitinase ABC I is not the amino acid sequence of any of SEQ ID NOs: 3-24.

32. The modified chondroitinase ABC I of claim 31, wherein the modified chondroitinase ABC I K cat or K M value is at least 20% different than a native chondroitinase ABC I k cat or K M value.

33. The modified chondroitinase ABC I of claim 32, wherein the modified chondroitinase ABC I k cat or K M value is at least 50% different than a native chondroitinase ABC I k cat or K M value.

34. The modified chondroitinase ABC I of claim 31, wherein the substrate is a glycosaminoglycan.

35. The modified chondroitinase ABC I of claim 34, wherein the glycosaminoglycan is a galactosaminoglycan.

36. The modified chondroitinase ABC I of any one of claims 28-33, wherein the nucleic acid of the modified chondroitinase is at least 90% homologous to the nucleic acid of a native chondroitinase ABC I.

37. The modified chondroitinase ABC I of any one of claims 28-33, wherein the nucleic acid of the modified chondroitinase is at least 95% homologous to the nucleic acid of a native chondroitinase ABC I.

38. The modified chondroitinase ABC I of any one of claims 28-33, wherein the nucleic acid of the modified chondroitinase is at least 97% homologous to the nucleic acid of a native chondroitinase ABC I.

39. The modified chondroitinase ABC I of any one of claims 28-33, wherein the nucleic acid of the modified chondroitinase is at least 99% homologous to the nucleic acid of a native chondroitinase ABC I.

40. A chondroitinase ABC I that selectively degrades chondroitin sulfate.

41. The chondroitinase ABC I of claim 40, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein the residue at position 388 has been substituted with alanine, lysine or arginine.

42. The chondroitinase ABC I of claim 40, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein the residue at position 389 has been substituted with alanine, lysine or arginine.

43. The chondroitinase ABC I of claim 40, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein the residue at position 500 has been substituted with alanine.

44. The chondroitinase ABC I of claim 40, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein the residue at position 653 has been substituted with alanine, lysine or arginine.

45. A chondroitinase ABC I that selectively degrades dermatan sulfate.

46. The chondroitinase ABC I of claim 45, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein the residue at position 560 has been substituted with alanine or lysine.

47. A chondroitinase ABC I that selectively degrades chondroitin 6-sulfate.

48. The chondroitinase ABC I of claim 47, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein the residue at position 500 has been substituted with cysteine or lysine.

49. A chondroitinase ABC I that selectively degrades chondroitin 4-sulfate.

50. The chondroitinase ABC I of claim 49, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein the residue at position 221 has been substituted with alanine.

51. The chondroitinase ABC I of claim 49, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein the residue at position 500 has been substituted with glutamine.

52. A chondroitinase ABC I with an altered calcium coordination motif.

53. The chondroitinase ABC I of claim 52, wherein the chondroitinase ABC I
has the amino acid sequence of a native chondroitinase ABC I, and wherein at least one residue at position 442, 444 or 490 has been substituted with a different amino acid than in the native chondroitinase ABC I.

54. The chondroitinase ABC I of claim 52, wherein the residues at position 442, 444 and 490 have been substituted with a different amino acid than in the native chondroitinase ABC I.

55. The chondroitinase ABC I of claim 53, wherein the at least one residue that is substituted is substituted with alanine.

56. A chondroitinase ABC I that has an amino acid sequence that comprises the amino acid sequence of SEQ ID NO: 2.

57. A polypeptide comprising the amino acid sequence of SEQ ID NO: 2 or a fragment thereof

58. A nucleic acid that encodes the polypeptide of claim 57.

59. The nucleic acid of claim 58, wherein the nucleic acid sequence is SEQ ID
NO: 1, a degenerate or complement thereof.

60. A vector comprising the nucleic acid of claim 58 or 59.

61. A composition comprising:
the chondroitinase ABC I of any one of claims 1-56 and a pharmaceutically acceptable carrier.

62. A composition comprising:
the chondroitinase ABC I of any one of claims 1-56 and a physiologically acceptable carrier.

63. A composition, comprising:
a chondroitinase and a divalent ion wherein the divalent ion is not zinc.

64. A composition, comprising:
a chondroitinase, a divalent ion and a pharmaceutically or physiologically acceptable carrier.

65. The composition of claim 63 or 64, wherein the divalent ion is calcium ion, manganese ion, copper ion, iron ion, barium ion, magnesium ion or a lanthanide.

66. The composition of claim 65, wherein the lanthanide is terbium or lutetium.

67. The composition of claim 65, wherein the calcium ion is in the form of CaC12.

68. The composition of claim 67, wherein the CaCI2 is present in the composition at a concentration of l, 2, 3, 4, 5, 6, 7, 8, 9 or 10 mM.

69. The composition of claim 67, wherein the CaCl2 is present at a concentration of at least 5 mM.

70. The composition of claim 67, wherein the CaCl2 is present at a concentration of at least 10 mM.

71. The composition of claim 70, wherein the CaCl2 is present at a concentration of 10 mM.

72. The composition of claim 63 or 64, wherein the chondroitinase is a chondroitinase B, chondroitinase ABC I or chondroitinase ABC II.

73. A composition, comprising:
a galactosaminoglycan-degrading enzyme and an enzyme stabilizer.

74. The composition of claim 73, wherein the enzyme stabilizer is a protease inhibitor.

75. The composition of claim 74, wherein the protease inhibitor is AEBSF, bestatin, E64 protease inhibitor, pepstatin A or phosphoramidon.

76. The composition of claim 73, wherein the enzyme stabilizer is a water mimic.

77. The composition of claim 76, wherein the water mimic is glycerol or dextran.

78. The composition of claim 73, wherein the galactosaminoglycan-degrading enzyme is a chondroitinase AC, chondroitinase B, chondroitinase ABC I, chondroitinase ABC II, chondro-4-sulfatase, chondro-6-sulfatase or hyaluronidase.

79. The composition of claim 73, further comprising a pharmaceutically or a physiologically acceptable carrier.

80. A method of degrading a glycosaminoglycan, comprising:
contacting a glycosaminoglycan with the chondroitinase ABC I of any one of claims 1-56 or the composition of any one of claims 61-79 in an amount effective to degrade the glycosaminoglycan.

81. The method of claim 80, wherein the method further comprises contacting the glycosaminoglycan with at least one other glycosaminoglycan-degrading enzyme.

82. The method of claim 80, wherein the method further comprises contacting the chondroitinase ABC I or glycosaminoglycan with zinc ion.

83. A method of degrading a glycosaminoglycan, comprising:
contacting a glycosaminoglycan with a chondroitinase in the presence of a divalent ion.

84. The method of claim 83, wherein the divalent ion is calcium ion, manganese ion, copper ion, iron ion, barium ion, magnesium ion, zinc ion or a lanthanide.

85. The method of claim 83, wherein the glycosaminoglycan is dermatan sulfate.

86. The method of claim 83, wherein the method further comprises contacting the chondroitinase ABC I or glycosaminoglycan with a second divalent ion.

87. The method of claim 86, wherein the second divalent ion is zinc ion.

88. The method of claim 83, wherein the method further comprises contacting the chondroitinase ABC I or glycosaminoglycan with a chelator.

89. The method of claim 88, wherein the chelator is EDTA or EGTA.

90. A method of degrading a glycosaminoglycan, comprising:
contacting a glycosaminoglycan with a galactosaminoglycan-degrading enzyme in the presence of an enzyme stabilizer.

91. The method of claim 90, wherein the enzyme stabilizer is a protease inhibitor.

92. The method of claim 91, wherein the protease inhibitor is AEBSF, bestatin, E64 protease inhibitor, pepstatin A or phosphoramidon.

93. The method of claim 90, wherein the enzyme stabilizer is a water mimic.

94. The method of claim 93, wherein the water mimic is glycerol or dextran.

95. A method of degrading a glycosaminoglycan, comprising:
contacting a glycosaminoglycan with a galactosaminoglycan-degrading enzyme in a solution with a pH greater than 7 but less than 8.

96. A method of degrading a glycosaminoglycan, comprising:
contacting a glycosaminoglycan with a galactosaminoglycan-degrading enzyme in the presence of a salt at a concentration of greater than 50 mM.

97. The method of claim 96, wherein the salt is at a concentration between 60-125 mM.

98. The method of claim 96, wherein the salt is at a concentration between 125-150 mM.

99. The method of claim 96, wherein the salt is at a concentration between 150-400 mM.

100. The method of claim 96, wherein the salt is at a concentration between 500 mM.

101. The method of claim 96, wherein the salt is at a concentration of 62.5 mM.

102. The method of claim 96, wherein the salt is at a concentration of 100 mM.

103. The method of claim 96, wherein the salt is at a concentration of 125 mM.

104. The method of claim 96, wherein the salt is at a concentration of 250 mM.

105. The method of claim 96, wherein the salt is sodium chloride, sodium sulfate, sodium acetate or ammonium sulfate.

I06. The method of any one of claims 80-105, wherein the contacting is carried out at a temperature between 38-45°C.

107. The method of any one of claims 80-105, wherein the contacting is carried out at a temperature between 38-50°C.

108. A degraded glycosaminoglycan prepared according to the method of any one of claims 80-107.

109. A pharmaceutical preparation, comprising:
the degraded glycosaminoglycan of claim 108 and a pharmaceutically acceptable carrier.

110. A method of selectively degrading chondroitin sulfate, comprising:
contacting the chondroitin sulfate with the chondroitinase ABA I of claim 40.

111. A method of selectively degrading dermatan sulfate, comprising:
contacting the dermatan sulfate with the chondroitinase ABC I of claim 45.

112. A method of selectively degrading chondroitin 6-sulfate:, comprising:
contacting the chondroitin 6-sulfate with the chondroitinase ABC I of claim 47.

113. A method of selectively degrading chondroitin 4-sulfate, comprising:
contacting the chondroitin 4-sulfate with the chondroitinase ABC I of claim 49.

114. A method of analyzing a sample of polysaccharides, comprising:
contacting the sample with the chondroitinase ABC I of any one of claims 1-56 or the composition of any one of claims 61-79 in an amount effective to degrade the glycosaminoglycan.

115. The method of claim 114, wherein the polysaccharides are glycosaminoglycans.

116. The method of claim 115, wherein the glycosaminoglycans are galactosaminoglycans.

117. The method of claim 114, wherein the method is a method for sequencing glycosaminoglycans.

118. The method of claim 114, wherein the method is a method identifying the presence of a particular polysaccharide in a sample.

119. The method of claim 114, wherein the method is a method for determining the purity of sample of polysaccharides.

120. The method of claim 114, wherein the method is a method for determining the composition of a sample of polysaccharides.

121. A method for promoting nerve regeneration, comprising:
administering to a subject in need thereof an effective amount of the composition of any one of claims 61, 64, 79 and 109 for promoting nerve regeneration.

122. The method of claim 121, wherein the subject has had a central nervous system injury.

123. The method of claim 121, wherein the subject has had a spinal cord injury

124. The method of claim 121, wherein the subject has a neuroclegenerative disorder.

125. The method of claim 121, wherein the subject has had a stroke.

126. The method of claim 121, wherein the nerve regeneration is axon regeneration.

127. A method for treating cancer, comprising:
administering to a subject in need thereof an effective amount of the composition of any one of claims 61, 64, 79 and 109 for treating cancer.

128. A method for inhibiting angiogenesis, comprising:
administering to a subject in need thereof an effective amount of the composition of any one of claims 61, 64, 79 and 109 for inhibiting angiogenesis.

129. A method for inhibiting coagulation, comprising:
administering to a subject in need thereof an effective amount of the composition of any one of claims 61, 64, 79 and 109 for inhibiting coagulation.

130. A method for treating psoriasis, comprising:
administering to a subject in need thereof an effective amount of the composition of any one of claims 61, 64, 79 and 109 for treating psoriasis.

131. A method for treating osteoarthritis, comprising:
administering to a subject in need thereof an effective amount of the composition of any one of claims 61, 64, 79 and 109 for treating osteoarthritis.

132. A method for treating maternal malarial infection, comprising:
administering to a subject in need thereof an effective amount of the composition of any one of claims 61, 64, 79 and 109 for treating maternal malarial infection.

133. A method for producing chondroitinase ABC l, comprising:
(a) harvesting cells that express chondroitinase ABC I, (b) lysing the cells, (c) obtaining supernatant, (d) applying the supernatant to a column, and (e) eluting the chondroitinase ABC I from the column;
wherein at least two of steps (a)-(e) also comprise putting the cells, supernatant or eluate on ice.

134. A method for producing chondroitinase ABC 1, comprising:
(a) harvesting cells that express chondroitinase ABC I, (b) lysing the cells, (c) obtaining supernatant, (d) applying the supernatant to a column, and (e) eluting the chondroitinase ABC I from the column;
wherein at least one of steps (a)-(e) is done in the presence of a prote=ase inhibitor.

135. The method of claim 134, wherein the protease inhibitor is AEBSF, bestatin, E64 protease inhibitor, pepstatin A or phosphoramidon.

136. An immobilized chondroitinase ABC I comprising:
the chondroitinase ABC I of any one of claims 1-56, and a solid support membrane, wherein the chondroitinase ABC I is immobilized on the solid support membrane.