CATH Classification

Domain Context

CATH Clusters

Superfamily Galactose-binding lectin
Functional Family

Enzyme Information

4.2.2.20
Chondroitin-sulfate-ABC endolyase.
based on mapping to UniProt P59807
Endolytic cleavage of (1->4)-beta-galactosaminic bonds between N-acetylgalactosamine and either D-glucuronic acid or L-iduronic acid to produce a mixture of Delta(4)-unsaturated oligosaccharides of different sizes that are ultimately degraded to Delta(4)-unsaturated tetra- and disaccharides.
-!- Degrades a variety of glycosaminoglycans of the chondroitin-sulfate- and dermatan-sulfate type. -!- Chondroitin sulfate, chondroitin-sulfate proteoglycan and dermatan sulfate are the best substrates but the enzyme can also act on hyaluronan at a much lower rate. -!- Keratan sulfate, heparan sulfate and heparin are not substrates. -!- In general, chondroitin sulfate (CS) and dermatan sulfate (DS) chains comprise a linkage region, a chain cap and a repeat region. -!- The repeat region of CS is a repeating disaccharide of glucuronic acid (GlcA) and N-acetylgalactosamine (GalNAc) [-4)GlcA(beta-1- 3)GalNAc(beta-1-](n), which may be O-sulfated on the C-4 and/or C-6 of GalNAc and C-2 of GlcA. -!- GlcA residues of CS may be epimerized to iduronic acid (IdoA) forming the repeating disaccharide [-4)IdoA(alpha-1-3)GalNAc(beta-1-](n) of DS. -!- Both the concentrations and locations of sulfate-ester substituents vary with glucosaminoglycan source. -!- The related enzyme EC 4.2.2.21 has the same substrate specificity but removes disaccharide residues from the non-reducing ends of both polymeric chondroitin sulfates and their oligosaccharide fragments produced by EC 4.2.2.20. -!- Formerly EC 4.2.2.4 and EC 4.2.99.6.

UniProtKB Entries (1)

P59807
CABC1_PROVU
Proteus vulgaris
Chondroitin sulfate ABC endolyase

PDB Structure

PDB 1HN0
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Crystal Structure of Proteus vulgaris Chondroitin Sulfate ABC Lyase I at 1.9 Angstroms Resolution
Huang, W., Lunin, V.V., Li, Y., Suzuki, S., Sugiura, N., Miyazono, H., Cygler, M.
J.Mol.Biol.