Improved thermostability and acetic acid tolerance of Escherichia coli via directed evolution of homoserine o-succinyltransferase.

ABSTRACT: In Escherichia coli, growth is limited at elevated temperatures mainly because of the instability of a single enzyme, homoserine o-succinyltransferase (MetA), the first enzyme in the methionine biosynthesis pathway. The metA gene from the thermophile Geobacillus kaustophilus cloned into the E. coli chromosome was found to enhance the growth of the host strain at elevated temperature (44 degrees C), thus confirming the limited growth of E. coli due to MetA instability. In order to improve E. coli growth at higher temperatures, we used random mutagenesis to obtain a thermostable MetA(E. coli) protein. Sequencing of the thermotolerant mutant showed five amino acid substitutions: S61T, E213V, I229T, N267D, and N271K. An E. coli strain with the mutated metA gene chromosomally inserted showed ac

SUBMITTER: Mordukhova EA 

PROVIDER: S-EPMC2607180 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature