The Journal of General and Applied Microbiology | |
Exploration of a N-terminal disulfide bridge to improve the thermostability of a GH11 xylanase from Aspergillus niger | |
Xin-Shu Zhu2  Chen-Yan Zhou2  Jing Kang2  Tong-Biao Li2  Yong-Tao Wang1  | |
[1] The First Affiliated Hospital, Xinxiang Medical University;School of Life Science and Technology, Xinxiang Medical University | |
关键词: disulfide bridge; site-directed mutagenesis; thermostability; xylanase; | |
DOI : 10.2323/jgam.62.83 | |
学科分类:微生物学和免疫学 | |
来源: Applied Microbiology, Molecular and Cellulrar Biosciences Research Foundation | |
【 摘 要 】
To improve the thermostability of xylanase XynZF-2 from Aspergillus niger XZ-3S, a disulfide bridge was introduced in the N-terminal domains by site-directed mutagenesis (V1C and E27C). Simultaneously, the active sites of XynZF-2 were predicted by bioinformatics software and verified by site-directed mutagenesis (E103D and E194D). The mutated active sites xynED- and the mutated disulfide bridge xynDC-encoding genes were constructed and expressed in Escherichia coli BL21 (DE3). Compared to the native xylanase, it was found that the residual activity of the mutated XynED was 0.17%. The optimum temperature of the variant XynDC was increased to 45°C from 40°C of XynZF-2. After treatment at 40°C for 60 min, the variant XynDC retained 66.77% of their original activity, while the XynZF-2 retained about 44.36% residual activity. t1/245°C of the variant XynDC also increased from 7 min to 14 min. The results of the mutated xylanases indicated that the active center of XynZF-2 mainly consisted of two catalytic residues (Glu103 and Glu194), and the introduction of a disulfide bridge in the N-terminal domains can improve the thermostability of XynZF-2.
【 授权许可】
Unknown
【 预 览 】
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