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Article
Mechanism of Xylobiose Hydrolysis by GH43 β-Xylosidase
The Journal of Physical Chemistry B
  • Ian J. Barker, Iowa State University
  • Luis Petersen, Iowa State University
  • Peter J. Reilly, Iowa State University
Document Type
Article
Publication Date
10-25-2010
DOI
10.1021/jp107886e
Abstract

Glycoside hydrolases cleave the glycosidic linkage between two carbohydrate moieties. They are among the most efficient enzymes currently known. β-Xylosidases from glycoside hydrolase family 43 hydrolyze the nonreducing ends of xylooligomers using an inverting mechanism. Although the general mechanism and catalytic amino acid residues of β-xylosidases are known, the nature of the reaction’s transition state and the conformations adopted by the glycon xylopyranosyl ring along the reaction pathway are still elusive. In this work, the xylobiose hydrolysis reaction catalyzed by XynB3, a β-xylosidase produced byGeobacillus stearothermophilus T-6, was explicitly modeled using first-principles quantum mechanics/molecular mechanics Car−Parrinello metadynamics. We present the reaction’s free energy surface and its previously undetermined reaction pathway. The simulations also show that the glycon xylopyranosyl ring proceeds through a 2,5B-type transition state with significant oxacarbenium ion character.

Comments

Posted with permission from The Journal of Physical Chemistry B, 114, no. 46 (2010): 15389–15393, doi:10.1021/jp107886e. Copyright 2010 American Chemical Society.

Copyright Owner
American Chemical Society
Language
en
Date Available
November 10, 2012
File Format
application/pdf
Citation Information
Ian J. Barker, Luis Petersen and Peter J. Reilly. "Mechanism of Xylobiose Hydrolysis by GH43 β-Xylosidase" The Journal of Physical Chemistry B Vol. 114 Iss. 46 (2010) p. 15389 - 15393
Available at: http://works.bepress.com/peter_reilly/13/