Engineering Recombinant Streptomyces coelicolor Malate Synthase with Improved Thermal Properties by Directed Mutagenesis

摘要

Streptomyces thermovulgaris malate synthase (stMS) is known to be more thermostable and thermoactive than S. coelicolor malate synthase (scMS). Therefore, based on the amino acid sequence of stMS, 3 scMS mutants, namely P186R, T8PL9P, and T8PL9PP186R, were created by site-directed mutagenesis in an attempt to engineer a more thermoactive and thermostable enzyme. An enzymatic analysis of the wild-type and mutant MS revealed that P186R and T8PL9PP186R were more thermoactive than the wild-type scMS and T8PL9P. Furthermore, all 3 mutants exhibited a greater thermostability than scMS, thereby suggesting that both R186 and P8P9 can cause increased thermostability in scMS.