Introduction Of Disulfide Bridge Enhances The Thermostability Of The Xylanase XynⅢ Aspergillus Niger

Although xylanases have widely used in the paper industry,the feed industry, the energy industry as well as in the foodstuff industry.their application in the paper,pulp and feed industries is limited somewate by certain enzymayic characteristics such as poor resistaince to high temperature.therefore,it is essential to improve the properties of xylanases for broader applications.This laboratory xylanase gene EU375728 with xylanase gene P55329 and P36217 which already reported introduction of disulfide bonds,through sequence alignment and designed seve pairs of mutant primers.In original protein sequence 30,47,128,130,174,177 and 178 amino acid replace for cystein(G30C;D47C;V128C ;S130C;N174C;N177C;F178C).Through the combination,expands with OE-PCR and PCR increases obtains 4 pairs of mutants gene ( G30C:D47C,S130C:N174C,S130C:N177C,V128C:F178C ) .The mutant gne cuts,the enzyme company,the transformation after the enzyme,swims the appraisal after the electrophoresis,the mutant gene truly clones to material particle pET20b.Will include the mutant gene the recorganization material particle to transform into the Escherichia coli,resrarch on the reorganization of the enzymatic properties, the main results were as follows:The thermostability of the mutant xylanzse(S130C/N174C and V128C/F178C)rased about foue times;but the disulfide bridge(S130C/N174C and V128C/F178C) decreased the thermostability; the disulfide bridge(S130C/N174C)increase the half-life of xynⅢfrom 12min to 31min at 50℃,and V128C/F178C increase the half-life to 25min.Overall,this research modified the xylanase from Aspergillus niger successfully and improvement of the thermostability.