Characterization of a Novel Mannose Isomerase from Stenotrophomonas rhizophila and Identification of Its Possible Catalytic Residues.

Autor: Wu, Yanchang, Huang, Zhaolin, Zhang, Wenli, Guang, Cuie, Chen, Qiuming, Mu, Wanmeng
Zdroj: Molecular Biotechnology; Jun2022, Vol. 64 Issue 6, p650-659, 10p
Abstrakt: D-Mannose has great value in the treatment of chronic diseases. D-Mannose isomerase can catalyze the bioconversion of D-fructose to D-mannose. Therefore, a novel D-mannose isomerase gene (Strh-MIase) from Stenotrophomonas rhizophila strain IS26 was expressed, purified, and characterized for the industrial production of D-mannose. The specific activities of the Strh-MIase for D-mannose and D-fructose were 437.5 ± 0.8 U/mg and 267.2 ± 0.7 U/mg. Its optimal temperature and pH were 50 °C and 7.0. The enzymatic bioconversion produced 25 g/L D-mannose from concentration D-fructose (100 g/L) in 6 h by recombinant Strh-MIase, resulting in a final yield of 25%. Sodium phosphate inhibition has little influence on D-mannose production when a high concentration of D-fructose is used as substrate. We demonstrate that the metal ions improve the efficiency of D-mannose isomerase because of the enhancement of its thermostability. Moreover, the possible catalytic residues of Strh-MIase were identified by site-directed mutagenesis. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index