Rational design of a thermophilic β-mannanase from Bacillus subtilis TJ-102 to improve its thermostability

Publication date: Available online 19 July 2018Source: Enzyme and Microbial TechnologyAuthor(s): Xiang-Chao Wang, Sheng-Ping You, Jia-Xing Zhang, Ye-Mei Dai, Cheng-Yu Zhang, Wei-Qi, Tong-Yi Dou, Rong-Xin Su, Zhi-Min HeAbstractA rational design method to improve β-mannanase (ManTJ102) thermostability was developed successfully in this study. The flexible area of residues 330-340 in ManTJ102 was firstly selected from analysis of molecular dynamics simulation and then the critical amino acid residue (Ala336Pro) with the lowest mutation energy was determined by virtual mutation, whose mutant was named as Mutant336. Afterward, the dynamics transition temperature (Tdtt) of ManTJ102 and Mutant336 was evaluated by simulated annealing and heating, and Mutant336 with higher Tdtt was implemented for experimental verification of the enzyme thermostability. As a result, the half-life of Mutant336 activity was 120 min at 60 °C, which was 24-fold of ManTJ102, and the irreversible thermal denaturation constant of Mutant336 was only about 2/5 of ManTJ102, indicating that Mutant336 has better thermostability than ManTJ102. Furthermore, Mutant336 has much higher β-mannanase activity and specific activity than ManTJ102. Therefore, Mutant336 was more suitable to further research for applications.Graphical Abstract

Source: Enzyme and Microbial Technology - July 20, 2018 Category: Biotechnology Source Type: research