title: The murG gene of Escherichia coli codes for the UDP-N-acetylglucosamine: N-acetylmuramyl-(pentapeptide) pyrophosphoryl-undecaprenol N-acetylglucosamine transferase involved in the membrane steps of peptidoglycan synthesis.
abstract: Physiological properties of the murG gene product of Escherichia coli were investigated. The inactivation of the murG gene rapidly inhibits peptidoglycan synthesis in exponentially growing cells. As a result, various alterations of cell shape are observed, and cell lysis finally occurs when the peptidoglycan content is 40% lower than that of normally growing cells. Analysis of the pools of peptidoglycan precursors reveals the concomitant accumulation of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylmuramyl-pentapeptide (UDP-MurNAc-pentapeptide) and, to a lesser extent, that of undecaprenyl-pyrophosphoryl-MurNAc-pentapeptide (lipid intermediate I), indicating that inhibition of peptidoglycan synthesis occurs after formation of the cytoplasmic precursors. The relative depletion of the second lipid intermediate, undecaprenyl-pyrophosphoryl-MurNAc-(pentapeptide)GlcNAc, shows that inactivation of the murG gene product does not prevent the formation of lipid intermediate I but inhibits the next reaction in which GlcNAc is transferred to lipid intermediate I. In vitro assays for phospho-MurNAc-pentapeptide translocase and N-acetylglucosaminyl transferase activities finally confirm the identification of the murG gene product as the transferase that catalyzes the conversion of lipid intermediate I to lipid intermediate II in the peptidoglycan synthesis pathway. Plasmids allowing for a high overproduction of the transferase and the determination of its N-terminal amino acid sequence were constructed. In cell fractionation experiments, the transferase is essentially associated with membranes when it is recovered.
authors.affiliation: Laboratoire de Biochimie Moleculaire et Cellulaire, URA 1131, Centre National de la Recherche Scientifique, Université Paris-Sud, Orsay, France.
authors.forename: D
authors.initials: D
authors.lastname: Mengin-Lecreulx
authors.forename: L
authors.initials: L
authors.lastname: Texier
authors.forename: M
authors.initials: M
authors.lastname: Rousseau
authors.forename: J
authors.initials: J
authors.lastname: van Heijenoort
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005964:Glucosyltransferases / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D006017:Glycolipids / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D017351:N-Acetylglucosaminyltransferases; D010457:Peptidoglycan / Q000096:biosynthesis* / Q000235:genetics; D010641:Phenotype; D010770:Phosphotransferases / Q000235:genetics; D010957:Plasmids; D013347:Subcellular Fractions / Q000737:chemistry; D017855:Transferases (Other Substituted Phosphate Groups)
chemical_list: D001425:Bacterial Outer Membrane Proteins; D006017:Glycolipids; D010457:Peptidoglycan; C052604:N-acetylglucosamine-pyrophosphorylundecaprenol; D005964:Glucosyltransferases; D017351:N-Acetylglucosaminyltransferases; C064057:UDP-N-acetylglucosamine-N-acetylmuramyl-(pentapeptide)pyrophosphoryl-undecaprenol N-acetylglucosamine transferase; D010770:Phosphotransferases; D017855:Transferases (Other Substituted Phosphate Groups); C100130:phospho-N-acetylmuramoyl pentapeptide transferase