English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

To improve the temperature characteristics and catalytic efficiency of a glycoside hydrolase family (GHF) 11 xylanase from  Aspergillus oryzae  (AoXyn11A), its variants were predicted based on in silico design. Firstly, Gly 21  with the maximum B-factor value, which was confirmed by molecular dynamics (MD) simulation on the three-dimensional structure of AoXyn11A, was subjected to site-saturation mutagenesis. Thus, one variant with the highest thermostability, AoXyn11A G21I , was selected from the mutagenesis library,  E. coli / Aoxyn11A   G21X  (X: any one of 20 amino acids). Secondly, based on the primary structure multiple alignment of AoXyn11A with seven thermophilic GHF11 xylanases, AoXyn11A Y13F  or AoXyn11A G21I–Y13F , was designed by replacing Tyr 13  in AoXyn11A or AoXyn11A G21I  with Phe. Finally, three variant-encoding genes,  Aoxyn11A   G21I ,  Aoxyn11A   Y13F  and  Aoxyn11A   G21I–Y13F , were constructed by two-stage whole-plasmid PCR method, and expressed in  Pichia pastoris  GS115, respectively. The temperature optimum ( T   opt ) of recombinant (re) AoXyn11A G21I–Y13F  was 60 °C, being 5 °C higher than that of reAoXyn11A G21I  or reAoXyn11A Y13F , and 10 °C higher than that of reAoXyn11A. The thermal inactivation half-life ( t   1/2 ) of reAoXyn11A G21I–Y13F  at 50 °C was 240 min, being 40-, 3.4- and 2.5-fold longer than those of reAoXyn11A, reAoXyn11A G21I  and reAoXyn11A Y13F . The melting temperature ( T   m ) values of reAoXyn11A, reAoXyn11A G21I , reAoXyn11A Y13F  and reAoXyn11A G21I–Y13F  were 52.3, 56.5, 58.6 and 61.3 °C, respectively. These findings indicated that the iterative mutagenesis of both Gly21Ile and Tyr13Phe improved the temperature characteristics of AoXyn11A in a synergistic mode. Besides those, the catalytic efficiency ( k   cat / K   m ) of reAoXyn11A G21I–Y13F  was 473.1 mL mg −1  s −1 , which was 1.65-fold higher than that of reAoXyn11A.   Electronic supplementary material  The online version of this article (doi:10.1186/s13568-017-0399-9) contains supplementary material, which is available to authorized users.

amb express

Improving the temperature characteristics and catalytic efficiency of a mesophilic xylanase from Aspergillus oryzae, AoXyn11A, by iterative mutagenesis based on in silico design