Itineraries of enzymatically and non-enzymatically catalyzed substitutions at O-glycopyranosidic bonds

被引：23

作者：

Nerinckx, Wim ^{[1
]}

Desmet, Tom ^{[1
]}

Claeyssens, Marc ^{[1
]}

机构：

[1] Univ Ghent, Dept Biochem Physiol & Microbiol, Lab Glycobiol, KL Ledeganckstr 35, B-9000 Ghent, Belgium

来源：

ARKIVOC | 2006年

关键词：

hydrolysis; glycoside hydrolase; mechanism; substrate/ligand complex;

D O I：

10.3998/ark.5550190.0007.d10

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Several crystal structures of glycoside hydrolases in complex with a substrate analog, or of inactive mutants complexed with a substrate, reveal non-ground state carbohydrate conformations within subsite -1 of the active site. These "frozen" local minima as preferred by the enzyme represent pre-transition-state situations along the reaction itinerary. Substantiated by theoretical considerations, this leads to the proposal that substitutions on beta-equatorial as well as alpha-axial D-O-glycopyranosidic bonds may always follow an itinerary that is predetermined by the original configuration at the anomeric center, where the formation of a transition state that is similar to a half-chair is always preceded by a conformational change away from the ground state.

引用

页码：90 / 116

页数：27

共 90 条

[31] Atomic (0.94 Å) resolution structure of an inverting glycosidase in complex with substrate [J].