Simultaneously Enhanced Thermostability and Catalytic Activity of Xylanase from Streptomyces rameus L2001 by Rigidifying Flexible Regions in Loop Regions of the N-Terminus.
Simultaneously Enhanced Thermostability and Catalytic Activity of Xylanase from Streptomyces rameus L2001 by Rigidifying Flexible Regions in Loop Regions of the N-Terminus.
复制标题
DOI：
10.1021/acs.jafc.3c03871
复制
发表时间：
2023-08
影响因子：
6.1
通讯作者：
Qiuhua Wu;Chengnan Zhang;Wenqi Dong;Hongyun Lu;Yue Yang;Weiwei Li;Youqiang Xu;Xiuting Li
中科院分区：
文献类型：
--
作者：
Qiuhua Wu;Chengnan Zhang;Wenqi Dong;Hongyun Lu;Yue Yang;Weiwei Li;Youqiang Xu;Xiuting Li
来自拉米链霉菌 L2001 的 GH11 木聚糖酶 XynA 具有良好的水解特性。但其热稳定性差阻碍了其在工业上的广泛应用。本研究通过合理组合突变体11YHDGYF16、23AP24/23SP24、32GP33构建了突变体Mut1和Mut2。这些组合突变体在80和90℃孵育12小时时残余酶活性超过85%，因此是迄今为止已知的最耐热的木聚糖酶。 N 端柔性的降低、整体刚性的增加以及 Mut1 和 Mut2 的表面净电荷可能是热稳定性提高的部分原因。此外，与野生型XynA相比，Mut1和Mut2的比活性和催化效率有所提高。 Mut1 和 Mut2 更宽的催化裂隙和增强的“拇指”灵活性可能是提高比活性和催化效率的部分原因。
The GH11 xylanase XynA from Streptomyces rameus L2001 has favorable hydrolytic properties. However, its poor thermal stability hinders its widespread application in industry. In this study, mutants Mut1 and Mut2 were constructed by rationally combining the mutations 11YHDGYF16, 23AP24/23SP24, and 32GP33. The residual enzyme activity of these combinational mutants was more than 85% when incubated at 80 and 90 °C for 12 h, and thus are the most thermotolerant xylanases known to date. The reduced flexibility of the N-terminus, increased overall rigidity, as well as the surface net charge of Mut1 and Mut2 may be partially responsible for the improved thermal stability. In addition, the specific activity and catalytic efficiency of Mut1 and Mut2 were improved compared with those of wild-type XynA. The broader catalytic cleft and enhanced flexibility of the "thumb" of Mut1 and Mut2 may be partially responsible for the improved specific activity and catalytic efficiency.