PEDS Advance Access originally published online on March 3, 2006
Protein Engineering Design and Selection 2006 19(5):205-210; doi:10.1093/protein/gzl002
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Mapping of residues involved in the interaction between the Bacillus subtilis xylanase A and proteinaceous wheat xylanase inhibitors
1Danisco, Edwin Rahrs Vej 38, DK-8220 Brabrand and 2Danisco, Langebrogade 1, DK-1001 Copenhagen C, Denmark
3 To whom correspondence should be addressed. E-mail: jens.frisbak.sorensen{at}danisco.com
The Bacillus subtilis xylanase A was subjected to site-directed mutagenesis, aimed at changing the interaction with Triticum aestivum xylanase inhibitor, the only wheat endogenous proteinaceous xylanase inhibitor interacting with this xylanase. The published structure of Bacillus circulans XynA was used to target amino acids surrounding the active site cleft of B.subtilis XynA for mutation. Twenty-two residues were mutated, resulting in 62 different variants. The catalytic activity of active mutants ranged from 563 to 5635 XU/mg and the interaction with T.aestivum xylanase inhibitor showed a similar variation. The results indicate that T.aestivum xylanase inhibitor interacts with several amino acid residues surrounding the active site of the enzyme. Three different amino acid substitutions in one particular residue (D11) completely abolished the interaction between T.aestivum xylanase inhibitor and B.subtilis xylanase A.
Keywords: endo-ß-1,4-xylanase/inhibition/site-directed mutagenesis/TAXI/XIP
Received August 23, 2005; revised January 25, 2006; accepted January 26, 2006.
Edited by Anthony Wilkinson