title: Lack of S-adenosylmethionine results in a cell division defect in Escherichia coli.
abstract: The enzyme S-adenosylmethionine (SAM) synthetase, the Escherichia coli metK gene product, produces SAM, the cell's major methyl donor. We show here that SAM synthetase activity is induced by leucine and repressed by Lrp, the leucine-responsive regulatory protein. When SAM synthetase activity falls below a certain critical threshold, the cells produce long filaments with regularly distributed nucleoids. Expression of a plasmid-carried metK gene prevents filamentation and restores normal growth to the metK mutant. This indicates that lack of SAM results in a division defect.
authors.affiliation: Biology Department, Concordia University Montreal, Quebec H3G 1M8. Neweb@Vax2.Concordia.Ca
authors.forename: E B
authors.initials: EB
authors.lastname: Newman
authors.forename: L I
authors.initials: LI
authors.lastname: Budman
authors.forename: E C
authors.initials: EC
authors.lastname: Chan
authors.forename: R C
authors.initials: RC
authors.lastname: Greene
authors.forename: R T
authors.initials: RT
authors.lastname: Lin
authors.forename: C L
authors.initials: CL
authors.lastname: Woldringh
authors.forename: R
authors.initials: R
authors.lastname: D'Ari
mesh_terms: D001426:Bacterial Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins; D007930:Leucine / Q000378:metabolism / Q000494:pharmacology; D051756:Leucine-Responsive Regulatory Protein; D008716:Methionine Adenosyltransferase / Q000187:drug effects / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000172:deficiency* / Q000235:genetics; D014157:Transcription Factors
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C497278:Lrp protein, E coli; D014157:Transcription Factors; D051756:Leucine-Responsive Regulatory Protein; D012436:S-Adenosylmethionine; D008716:Methionine Adenosyltransferase; D007930:Leucine