RRC ID 35577
著者 Sang PB, Varshney U.
タイトル Biochemical properties of MutT2 proteins from Mycobacterium tuberculosis and M. smegmatis and their contrasting antimutator roles in Escherichia coli.
ジャーナル J Bacteriol
Abstract Mycobacterium tuberculosis, the causative agent of tuberculosis, is at increased risk of accumulating damaged guanine nucleotides such as 8-oxo-dGTP and 8-oxo-GTP because of its residency in the oxidative environment of the host macrophages. By hydrolyzing the oxidized guanine nucleotides before their incorporation into nucleic acids, MutT proteins play a critical role in allowing organisms to avoid their deleterious effects. Mycobacteria possess several MutT proteins. Here, we purified recombinant M. tuberculosis MutT2 (MtuMutT2) and M. smegmatis MutT2 (MsmMutT2) proteins from M. tuberculosis (a slow grower) and M. smegmatis (fast growing model mycobacteria), respectively, for their biochemical characterization. Distinct from the Escherichia coli MutT, which hydrolyzes 8-oxo-dGTP and 8-oxo-GTP, the mycobacterial proteins hydrolyze not only 8-oxo-dGTP and 8-oxo-GTP but also dCTP and 5-methyl-dCTP. Determination of kinetic parameters (Km and Vmax) revealed that while MtuMutT2 hydrolyzes dCTP nearly four times better than it does 8-oxo-dGTP, MsmMutT2 hydrolyzes them nearly equally. Also, MsmMutT2 is about 14 times more efficient than MtuMutT2 in its catalytic activity of hydrolyzing 8-oxo-dGTP. Consistent with these observations, MsmMutT2 but not MtuMutT2 rescues E. coli for MutT deficiency by decreasing both the mutation frequency and A-to-C mutations (a hallmark of MutT deficiency). We discuss these findings in the context of the physiological significance of MutT proteins.
巻・号 195(7)
ページ 1552-60
公開日 2013-4-1
DOI 10.1128/JB.02102-12
PII JB.02102-12
PMID 23354752
PMC PMC3624529
MeSH Amino Acid Sequence Bacterial Proteins / metabolism* Deoxycytosine Nucleotides / metabolism Deoxyguanine Nucleotides / metabolism Escherichia coli / enzymology Escherichia coli / genetics Guanosine Triphosphate / analogs & derivatives Guanosine Triphosphate / metabolism Kinetics Molecular Sequence Data Mutation* Mycobacterium smegmatis / enzymology* Mycobacterium tuberculosis / enzymology* Oxidation-Reduction Recombinant Proteins / genetics Recombinant Proteins / metabolism Sequence Homology, Amino Acid
IF 3.006
引用数 21
WOS 分野 MICROBIOLOGY
リソース情報
原核生物(大腸菌) JW0097-KC