深入了解暴露表面带电残基在GH11木聚糖酶耐碱性中的作用
Insights Into the Role of Exposed Surface Charged Residues in the Alkali-Tolerance of GH11 Xylanase.
作者信息
Wu Xiuyun, Zhang Qun, Zhang Lanzeng, Liu Shijia, Chen Guanjun, Zhang Huaiqiang, Wang Lushan
机构信息
State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China.
Taishan College, Shandong University, Jinan, China.
出版信息
Front Microbiol. 2020 May 8;11:872. doi: 10.3389/fmicb.2020.00872. eCollection 2020.
Thermostable and alkaline- or acid-stable xylanases are more advantageous in agricultural and industrial fields. In this study, a rational structure-based design was conducted based on a thermostable GH11 xylanase XynA from to improved pH-tolerance. Four mutant enzymes (P1, P2, P3, and P4) and five variants (N1, N2, N3, N4, and N5) were constructed by substituting surface charged residue combinations using site-directed mutagenesis. Compared to the native enzyme, two mutants P1 and P2 showed higher acid tolerance, especially at pH 3.0, presented 50 and 40% of their maximum activity, respectively. In addition, four mutants N1, N2, N3 and N4 had higher tolerance than the native enzyme to alkaline environments (pH 7.0-9.0). At pH 9.0, the residual activities of N1, N2, N3, and N4 were 86, 78, 77, and 66%, respectively. In summary, an improved pH-tolerance design principle is being reported.
耐热以及耐碱或耐酸的木聚糖酶在农业和工业领域更具优势。在本研究中，基于来自[具体来源未给出]的耐热GH11木聚糖酶XynA进行了基于结构的合理设计，以提高pH耐受性。通过定点诱变替换表面带电残基组合构建了四种突变酶（P1、P2、P3和P4）和五种变体（N1、N2、N3、N4和N5）。与天然酶相比，两种突变体P1和P2表现出更高的耐酸性，尤其是在pH 3.0时，分别呈现出其最大活性的50%和40%。此外，四种突变体N1、N2、N3和N4比天然酶对碱性环境（pH 7.0 - 9.0）具有更高的耐受性。在pH 9.0时，N1、N2、N3和N4的残余活性分别为86%、78%、77%和66%。总之，本文报道了一种改进的pH耐受性设计原则。
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