Patent ID: 10968439

Abstract:
The present invention relates to the technical field of protein engineering, and, in particular, to a xylanase mutant with improved heat tolerance. The present invention artificially introduces two or three unnatural disulfide bridges into xylanase by site-directed mutagenesis and obtains the mutants XynA1 and XynA2 with improved heat tolerance, especially the mutant XynA2 into which three disulfide bridges are introduced, achieving residual enzyme activity of 75% after treatment at 80° C. for 5 min, 72% higher than the residual enzyme activity of the mutant XynA1. The present invention further obtains, by screening, three mutation sites Q51N, H143K, and Q161F that can significantly increase the heat tolerance of mutants, and introduction of the mutation sites into the XynA1 and XynA2 xylanases, whether at a single point or a combination of two points or a combination of three points, can effectively improve the heat tolerance of the mutants.