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

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19 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)9-15
Number of pages7
JournalFEMS Microbiology Letters
Volume239
Issue number1
DOIs
Publication statusPublished - 1 Oct 2004
Externally publishedYes

Keywords

  • Aspergillus niger xylanase
  • Enzyme inhibition
  • Family 11 glycoside hydrolase
  • Pichia pastoris
  • Proteinaceous inhibitors
  • Site-directed mutagenesis

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