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Enhanced thermostability of a mesophilic xylanase by N ‐terminal replacement designed by molecular dynamics simulation
Author(s) -
Yin Xin,
Li JianFang,
Wang JunQing,
Tang CunDuo,
Wu MinChen
Publication year - 2013
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.6134
Subject(s) - thermostability , xylanase , mesophile , pichia pastoris , chemistry , molecular dynamics , enzyme , biochemistry , food science , biology , gene , recombinant dna , bacteria , genetics , computational chemistry
Background Xylanases have attracted much attention owing to their potential applications. The applicability of xylanases, however, was bottlenecked by their low stabilities at high temperature or extreme pH . The purpose of this work was to enhance the thermostability of a mesophilic xylanase by N ‐terminal replacement . Results The thermostability of AoXyn11 , a mesophilic family 11 xylanase from Aspergillus oryzae , was enhanced by replacing its N ‐terminal segment with the corresponding one of Ev Xyn11 TS , a hyperthermotolerant family 11 xylanase. A hybrid xylanase with high thermostability, NhXyn11 57 , was predicted by molecular dynamics (MD) simulation. An NhXyn11 57 ‐encoding gene, Nhxyn11 57 , was then constructed as designed theoretically, and overexpressed in Pichia pastoris . The temperature optimum of recombinant NhXyn11 57 (re‐NhXyn11 57 ) was 75 °C, much higher than that of re‐AoXyn11. Both xylanases were thermostable at 65 and 40 °C, respectively. Additionally, the pH optimum and stability of re‐NhXyn11 57 were 5.5 and at a range of 4.0–8.5. Its activity was not significantly affected by metal ions tested and EDTA, but strongly inhibited by Mn 2+ and Ag + . Conclusion This work obviously enhanced the thermostability of a mesophilic xylanase, making re‐NhXyn11 57 a promising candidate for industrial processes. It also provided an effective technical strategy for improving thermostabilities of other mesophilic enzymes. © 2013 Society of Chemical Industry