Enhancing the thermostability of a novel beta-agarase AgaB through directed evolution |
| |
Authors: | Shi Chao Lu Xinzhi Ma Cuiping Ma Yiming Fu Xiaoyan Yu Wengong |
| |
Affiliation: | (1) The Department of Molecular Biology, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China;(2) College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China |
| |
Abstract: | To increase the thermostability of β-agarase AgaB by directed evolution, the mutant gene libraries were generated by error-prone polymerase chain reaction (PCR) and deoxyribonucleic acid (DNA) shuffling. Mutants with high thermostability were screened by a simple method based on agarase-degrading agar to generate a clear zone on the agar plate. A mutant S2 was obtained through two rounds of error-prone PCR and a single round of DNA shuffling and selection. It has higher thermostability and slightly increased catalytic activity than wild-type AgaB. Melting temperature (T m) of S2, as determined by circular dichroism, is 4.6 °C higher than that of wild-type AgaB, and the half-life of S2 is 350 min at 40 °C, which is 18.4-fold longer than that of the wild-type enzyme. Saturation mutagenesis and hydrophobic cluster analysis indicated that hydrophobic interaction might be the key factor that enhances the enzyme stability. |
| |
Keywords: | Agarase Thermostability Directed evolution Clear zone screening DNA shuffling |
本文献已被 PubMed SpringerLink 等数据库收录! |
|