An unusual mechanism of glycoside hydrolysis involving redox and elimination steps by a family 4 beta-glycosidase from Thermotoga maritima

Vivian L Y Yip; Annabelle Varrot; Gideon J Davies; Shyamala S Rajan; Xiaojing Yang; John Thompson; Wayne F Anderson; Stephen G Withers

doi:10.1021/ja047632w

An unusual mechanism of glycoside hydrolysis involving redox and elimination steps by a family 4 beta-glycosidase from Thermotoga maritima

J Am Chem Soc. 2004 Jul 14;126(27):8354-5. doi: 10.1021/ja047632w.

Authors

Vivian L Y Yip¹, Annabelle Varrot, Gideon J Davies, Shyamala S Rajan, Xiaojing Yang, John Thompson, Wayne F Anderson, Stephen G Withers

Affiliation

¹ Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 1Z1.

PMID: 15237973
DOI: 10.1021/ja047632w

Abstract

Among the numerous well-characterized families of glycosidases, family 4 appears to be the anomaly, requiring both catalytic NAD+ and a divalent metal for activity. The unusual cofactor requirement prompted the proposal of a mechanism involving key NAD+-mediated redox steps as well as elimination of the glycosidic oxygen. Primary kinetic isotope effects for the 2- and 3-deutero substrate analogues, isotopic exchange with solvent, and structural analysis of a 6-phospho-beta-glucosidase, BglT (E.C. 3.2.1.6), provided evidence in support of the proposed mechanism, which has striking resemblances to that of the sugar dehydratases. Furthermore, analysis of the stereochemical outcome indicated that family 4 enzymes are retaining glycosidases.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Glucosidases / chemistry*
Glucosidases / metabolism*
Glycosides / chemistry*
Glycosides / metabolism*
Hydrolysis
Models, Molecular
Oxidation-Reduction
Thermotoga maritima / enzymology*

Substances

Glycosides
Glucosidases
6-phospho-beta-glucosidase