title: A riboswitch regulates expression of the coenzyme B12-independent methionine synthase in Mycobacterium tuberculosis: implications for differential methionine synthase function in strains H37Rv and CDC1551.
abstract: We observed vitamin B(12)-mediated growth inhibition of Mycobacterium tuberculosis strain CDC1551. The B(12) sensitivity was mapped to a polymorphism in metH, encoding a coenzyme B(12)-dependent methionine synthase. Vitamin B(12)-resistant suppressor mutants of CDC1551 containing mutations in a B(12) riboswitch upstream of the metE gene, which encodes a B(12)-independent methionine synthase, were isolated. Expression analysis confirmed that the B(12) riboswitch is a transcriptional regulator of metE in M. tuberculosis.
authors.affiliation: Molecular Mycobacteriology Research Unit, National Health Laboratory Service, P.O. Box 1038, Johannesburg 2000, South Africa. digby.warner@nhls.ac.za
authors.forename: Digby F
authors.initials: DF
authors.lastname: Warner
authors.forename: Suzana
authors.initials: S
authors.lastname: Savvi
authors.forename: Valerie
authors.initials: V
authors.lastname: Mizrahi
authors.forename: Stephanie S
authors.initials: SS
authors.lastname: Dawes
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000096:biosynthesis* / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D003038:Cobamides / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D006131:Growth Inhibitors / Q000494:pharmacology; D015394:Molecular Structure; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D009690:Nucleic Acid Conformation; D012329:RNA, Bacterial / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D013489:Suppression, Genetic; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D003038:Cobamides; D006131:Growth Inhibitors; D012329:RNA, Bacterial; D012333:RNA, Messenger; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase