Characterization and regulation of the osmolyte betaine synthesizing enzymes GSMT and SDMT from halophilic methanogen Methanohalophilus portucalensis.

ABSTRACT: The halophilic methanoarchaeon Methanohalophilus portucalensis can synthesize the osmolyte betaine de novo in response to extracellular salt stress. Betaine is generated by the stepwise methylation of glycine to form sarcosine, N, N-dimethylglycine and betaine by using S-adenosyl-L-methionine (AdoMet) as the methyl donor. The complete gene cluster of Mpgsmt-sdmt was cloned from Southern hybridization and heterologous expressed in E. coli respectively. The recombinant MpGSMT and MpSDMT both retained their in vivo functional activities in E. coli BL21(DE3)RIL to synthesize and accumulate betaine and conferred elevated survival ability in betaine transport deficient mutant E. coli MKH13 under high salt stress. The dramatic activating effects of sodium and potassium ions on the in vitro methyl

SUBMITTER: Lai SJ 

PROVIDER: S-EPMC3176816 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature