Structural insights into the catalytic reaction that is involved in the reorientation of Trp238 at the substrate-binding site in GH13 dextran glucosidase

被引：14

作者：

Kobayashi, Momoko ^{[1
]}

Saburi, Wataru ^{[2
]}

Nakatsuka, Daichi ^{[2
]}

Hondoh, Hironori ^{[2
]}

Kato, Koji ^{[1
,3
]}

Okuyama, Masayuki ^{[2
]}

Mori, Haruhide ^{[2
]}

Kimura, Atsuo ^{[2
]}

Yao, Min ^{[1
,3
]}

机构：

[1] Hokkaido Univ, Grad Sch Life Sci, Kita Ku, Sapporo, Hokkaido 0600810, Japan

[2] Hokkaido Univ, Res Fac Agr, Kita Ku, Sapporo, Hokkaido 0608589, Japan

[3] Hokkaido Univ, Fac Adv Life Sci, Kita Ku, Sapporo, Hokkaido 0600810, Japan

来源：

FEBS LETTERS | 2015年 / 589卷 / 04期

基金：

日本学术振兴会;

关键词：

Retaining glycosidase; Dextran glucosidase; Glycoside hydrolase family 13; Glucosyl-enzyme intermediate; transglucosylation; Acceptor specificity; VULGARIS R-47 ALPHA-AMYLASE-1; COVALENT INTERMEDIATE; COMPLEX STRUCTURES; CRYSTAL-STRUCTURE; MECHANISM; DEMONSTRATE; PROVIDE; ENZYME;

D O I：

10.1016/j.febslet.2015.01.005

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Streptococcus mutans dextran glucosidase (SmDG) belongs to glycoside hydrolase family 13, and catalyzes both the hydrolysis of substrates such as isomaltooligosaccharides and subsequent transglucosylation to form alpha-(1 -> 6)-glucosidic linkage at the substrate non-reducing ends. Here, we report the 2.4 angstrom resolution crystal structure of glucosyl-enzyme intermediate of SmDG. In the obtained structure, the Trp238 side-chain that constitutes the substrate-binding site turned away from the active pocket, concurrently with conformational changes of the nucleophile and the acid/base residues. Different conformations of Trp238 in each reaction stage indicated its flexibility. Considering the results of kinetic analyses, such flexibility may reflect a requirement for the reaction mechanism of SmDG. (C) 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

引用

页码：484 / 489

页数：6