Three-dimensional structure of an alkaline xylanase Xyn11A-LC from alkalophilic Bacillus sp SN5 and improvement of its thermal performance by introducing arginines substitutions
Three-dimensional structure of an alkaline xylanase Xyn11A-LC from alkalophilic Bacillus sp SN5 and improvement of its thermal performance by introducing arginines substitutions
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DOI：
10.1007/s10529-014-1512-7
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发表时间：
2014-07-01
影响因子：
2.7
通讯作者：
Ma, Yanhe
中科院分区：
文献类型：
--
作者：
Bai, Wenqin;Zhou, Cheng;Ma, Yanhe
嗜碱芽孢杆菌的碱性木聚糖酶Xyn11A-LC。SN5在大肠杆菌中表达、纯化和结晶。晶体结构测定的分辨率为1.49。Xyn11A-LC具有典型的11家族木聚糖酶的β-凝胶卷曲结构。为了提高SB3的热稳定性和亲热性，通过在蛋白质表面的不同侧边引入三种精氨酸，构建了SB3突变体。在65℃、pH 8.0的Tris/HCl缓冲液中，野生型和SB3的半衰期分别为22min和68min。CD光谱分析表明，野生型和SB3的熔融温度分别为55.3和66.9 A℃。这些结果表明，精氨酸的引入提高了Xyn11A-LC的亲热性和热稳定性。
The alkaline xylanase Xyn11A-LC from the alkalophilic Bacillus sp. SN5 was expressed in E. coli, purified and crystallized. The crystal structure was determined at a resolution of 1.49 . Xyn11A-LC has the beta-jelly roll structure typical of family 11 xylanases. To improve its thermostability and thermophilicity, a mutant SB3 was constructed by introducing three arginines on the different sides of the protein surface. SB3 increased the optimum temperature by 5 A degrees C. The wild type and SB3 had the half-lives of 22 and 68 min at 65 A degrees C at pH 8.0 (Tris/HCl buffer), respectively. CD spectroscopy revealed that the melting temperature (T (m)) of the wild type and SB3 were 55.3 and 66.9 A degrees C, respectively. These results showed that the introduction of arginines enhance the thermophilicity and thermostability of Xyn11A-LC.