The Journal of General and Applied Microbiology
Online ISSN : 1349-8037
Print ISSN : 0022-1260
ISSN-L : 0022-1260
Full Papers
Effect of introducing disulfide bridges in C-terminal structure on the thermostability of xylanase XynZF-2 from Aspergillus niger
Liutengzi CaiMishuai ZhangTianci ShaoYou HeJingyi LiBingjie RenChenyan Zhou
Author information

2019 Volume 65 Issue 5 Pages 240-245


In this study, a mutant xylanase of high thermostability was obtained by site-directed mutagenesis. The homologous 3D structure of xylanase was successfully modeled and the mutation sites were predicted using bioinformatics software. Two amino acids of XynZF-2 were respectively substituted by cysteines (T205C and A52C) and a disulfide bridge was introduced into the C-terminal of XynZF-2. The mutant gene xynZFTA was cloned into pPIC9K and expressed in P. pastoris. The optimum temperature of the variant XynZFTA was improved from 45°C to 60°C, and XynZFTA retained greater than 90.0% activity (XynZF-2 retained only 50.0% activity) after treatment at 50°C for 5 min. The optimum pH of mutant xylanase was similar to XynZF-2 (pH = 5.0). The pH stability span (5.0~7.0) of the mutant xylanase was increased to 3.0~9.0. Overall, the results implied that the introduction of a disulfide bridge in the C-terminal structure improved the thermostability and pH stability of XynZF-2.

Information related to the author
© 2019, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
Previous article Next article