Xylanase mutants

Abstract

The invention relates to the technical field of protein engineering modification, in particular to xylanase mutants with improved heat resistance. Two or more unnatural disulfide bridges are manuallyintroduced into xylanase with a site-directed mutation method, the mutants XynA1 and XynA2 with improved heat resistance are obtained, and particularly, for the mutant XynA2 with three disulfide bridges introduced, enzyme activity residual rate of the mutant XynA2 after 5 min treatment at 80 DEG C is as high as 75% and is increased by 72% compared with that of the mutant XynA1. Three mutation sites Q51N, H143K and Q161F capable of improving heat resistance of the mutants remarkably are obtained by further screening, xylanase XynA1 and xylanase XynA2 are introduced into the mutation sites in amode of single-point, two-point combination or three-point combination, and heat resistance can be effectively improved.

Description

technical field

[0001] The invention relates to the technical field of protein engineering, in particular to a xylanase mutant with improved heat resistance. Background technique

[0002] Xylan is the main component of plant hemicellulose, widely present in crop wastes such as corncobs, bagasse, wheat bran, straw, etc., because xylanase can decompose xylan into oligomeric wood of different lengths Sugar and xylose, this product has important economic value, and these available resources can be fully utilized by xylanase to exert its potential application value, and the research of xylanase has also received sufficient attention.

[0003] Xylanases are glycosyl hydrolases that hydrolyze β-1,4-linked xylopyranoside chains, have been shown to exist in at least hundreds of different organisms, and can be economically produced on a large scale. Together with other glycosyl hydrolases, they form a superfamily comprising more than 40 different enzyme families. Trichoderma reesei ...

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