Substrate specificity of Chondroitinase ABC I based on analyses of biochemical reactions and crystal structures in complex with disaccharides.
Glycobiology
; 31(11): 1571-1581, 2021 12 18.
Article
in En
| MEDLINE
| ID: mdl-34392362
ABSTRACT
Chondroitinase ABC I (cABC-I) is the enzyme which cleaves the ß-1,4 glycosidic linkage of chondroitin sulfate (CS) by ß-elimination. To elucidate more accurately the substrate specificity of cABC-I, we evaluated the kinetic parameters of cABC-I and its reactivity with CS isomers displaying less structural heterogeneity as substrates, e.g., approximately 90 percent of disaccharide units in Chondroitin sulfate A (CSA) or Chondroitin sulfate C (CSC) is D-glucuronic acid and 4-O-sulfated N-acetyl galactosamine (GalNAc) (A-unit) or D-glucuronic acid and 6-O-sulfated GalNAc (C-unit), respectively. cABC-I showed the highest reactivity to CSA and CSC among all CS isomers, and the kcat/Km of cABC-I was higher for CSA than for CSC. Next, we determined the crystal structures of cABC-I in complex with CS disaccharides, and analyzed the crystallographic data in combination with molecular docking data. Arg500 interacts with 4-O-sulfated and 6-O-sulfated GalNAc residues. The distance between Arg500 and the 4-O-sulfate group was 0.8 Å shorter than that between Arg500 and the 6-O-sulfated group. Moreover, it is likely that the 6-O-sulfated group is electrostatically repulsed by the nearby Asp490. Thus, we demonstrated that cABC-I has the highest affinity for the CSA richest in 4-O-sulfated GalNAc residues among all CS isomers. Recently, cABC-I was used to treat lumbar disc herniation. The results provide useful information to understand the mechanism of the pharmacological action of cABC-I.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Chondroitin Sulfates
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Chondroitin ABC Lyase
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Disaccharides
/
Molecular Docking Simulation
Limits:
Humans
Language:
En
Journal:
Glycobiology
Journal subject:
BIOQUIMICA
Year:
2021
Document type:
Article
Affiliation country:
Japan