Functional importance of Asp37 from a family 11 xylanase in the binding to two proteinaceous xylanase inhibitors from wheat

Tariq A Tahir; Anne Durand; Kurt Gebruers; Alain Roussel; Gary Williamson; Nathalie Juge

doi:10.1016/j.femsle.2004.07.051

Functional importance of Asp37 from a family 11 xylanase in the binding to two proteinaceous xylanase inhibitors from wheat

FEMS Microbiol Lett. 2004 Oct 1;239(1):9-15. doi: 10.1016/j.femsle.2004.07.051.

Authors

Tariq A Tahir¹, Anne Durand, Kurt Gebruers, Alain Roussel, Gary Williamson, Nathalie Juge

Affiliation

¹ Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.

PMID: 15451095
DOI: 10.1016/j.femsle.2004.07.051

Abstract

Aspergillus niger xylanase is a target enzyme of the two wheat proteinaceous inhibitors, XIP-I and TAXI-I. We previously suggested that the xylanase "thumb" region was XIP-I binding site. Here, we expressed the Asp37Ala mutant in Pichia pastoris and showed that the mutation abolished the enzyme capacity to interact with both inhibitors, suggesting a direct contact at the active site. The mutant pH profile was altered, confirming the key role of Asp37 in determining the pH optima of glycoside hydrolase family 11. The results are consistent with a competitive inhibition mode and underline the strategic importance of Asp37 in the inhibition mechanism.

Publication types

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

MeSH terms

Aspergillus niger / enzymology*
Aspergillus niger / genetics
Binding Sites
Carrier Proteins / metabolism*
Endo-1,4-beta Xylanases / chemistry*
Endo-1,4-beta Xylanases / genetics
Endo-1,4-beta Xylanases / metabolism*
Enzyme Inhibitors / metabolism*
Intracellular Signaling Peptides and Proteins
Models, Molecular
Mutagenesis, Site-Directed
Pichia / enzymology
Pichia / genetics
Plant Proteins / metabolism*

Substances

Carrier Proteins
Enzyme Inhibitors
Intracellular Signaling Peptides and Proteins
Plant Proteins
TAXI I protein, Triticum aestivum
XIP-I protein, Triticum aestivum
Endo-1,4-beta Xylanases