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 language | English |
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Pages (from-to) | 9-15 |
Number of pages | 7 |
Journal | FEMS Microbiology Letters |
Volume | 239 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Oct 2004 |
Externally published | Yes |
Keywords
- Aspergillus niger xylanase
- Enzyme inhibition
- Family 11 glycoside hydrolase
- Pichia pastoris
- Proteinaceous inhibitors
- Site-directed mutagenesis