7EIP

Crystal structure of ligand-free chondroitin ABC lyase I

7EIP の概要

• エントリーDOI: 10.2210/pdb7eip/pdb
• 分子名称: Chondroitin sulfate ABC endolyase, ACETATE ION, MAGNESIUM ION, ... (4 entities in total)
• 機能のキーワード: polysaccharide lyase family 8, carbohydrate binding, lyase
• 由来する生物種: Proteus vulgaris
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 115358.78

構造登録者

Takashima, M.,Miyanaga, A.,Eguchi, T. (登録日: 2021-03-31, 公開日: 2021-08-25, 最終更新日: 2023-11-29)

主引用文献

Takashima, M.,Watanabe, I.,Miyanaga, A.,Eguchi, T.
Substrate specificity of Chondroitinase ABC I based on analyses of biochemical reactions and crystal structures in complex with disaccharides.
Glycobiology, 31:1571-1581, 2021

PubMed Abstract: Chondroitinase ABC I (cABC-I) is the enzyme which cleaves the β-1,4 glycosidic linkage of chondroitin sulfate (CS) by β-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.

PubMed: 34392362
DOI: 10.1093/glycob/cwab086

実験手法

X-RAY DIFFRACTION (1.88 Å)