Enhancing the Thermostability of Feruloyl Esterase EstF27 by Directed Evolution and the Underlying Structural Basis
Cao, L.C., Chen, R., Xie, W., Liu, Y.H.(2015) J Agric Food Chem 63: 8225-8233
- PubMed: 26329893 
- DOI: https://doi.org/10.1021/acs.jafc.5b03424
- Primary Citation of Related Structures:  
4ZRS - PubMed Abstract: 
To improve the thermostability of EstF27, two rounds of random mutagenesis were performed. A thermostable mutant, M6, with six amino acid substitutions was obtained. The half-life of M6 at 55 °C is 1680 h, while that of EstF27 is 0.5 h. The Kcat/Km value of M6 is 1.9-fold higher than that of EstF27. The concentrations of ferulic acid released from destarched wheat bran by EstF27 and M6 at their respective optimal temperatures were 223.2 ± 6.8 and 464.8 ± 11.9 μM, respectively. To further understand the structural basis of the enhanced thermostability, the crystal structure of M6 is determined at 2.0 Å. Structural analysis shows that a new disulfide bond and hydrophobic interactions formed by the mutations may play an important role in stabilizing the protein. This study not only provides us with a robust catalyst, but also enriches our knowledge about the structure-function relationship of feruloyl esterase.
Organizational Affiliation: 
School of Life Sciences, ‡State Key Laboratory for Biocontrol, School of Life Sciences, and §South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University , Guangzhou 510275, People's Republic of China.