title: Murein segregation in Escherichia coli.
abstract: Peptidoglycan (murein) segregation has been studied by means of a new labeling method. The method relies on the ability of Escherichia coli cells to incorporate D-Cys into macromolecular murein. The incorporation depends on a periplasmic amino acid exchange reaction. At low concentrations, D-Cys is innocuous to the cell. The distribution of modified murein in purified sacculi can be traced and visualized by immunodetection of the -SH groups by fluorescence and electron microscopy techniques. Analysis of murein segregation in wild-type and cell division mutant strains revealed that murein in polar caps is metabolically inert and is segregated in a conservative fashion. Elongation of the sacculus apparently occurs by diffuse insertion of precursors over the cylindrical part of the cell surface. At the initiation of cell division, there is a FtsZ-dependent localized activation of murein synthesis at the potential division sites. Penicillin-binding protein 3 and the products of the division genes ftsA and ftsQ are dispensable for the activation of division sites. As a consequence, under restrictive conditions ftsA,ftsI,or ftsQ mutants generate filamentous sacculi with rings of all-new murein at the positions where septa would otherwise develop.
authors.affiliation: Centro de Biología Molecular Severo Ochoa Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Facultad de Ciencias, Spain. madepedro@mvax.cbm.uam.es
authors.forename: M A
authors.initials: MA
authors.lastname: de Pedro
authors.forename: J C
authors.initials: JC
authors.lastname: Quintela
authors.forename: J V
authors.initials: JV
authors.lastname: Höltje
authors.forename: H
authors.initials: H
authors.lastname: Schwarz
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002352:Carrier Proteins; D002455:Cell Division; D002458:Cell Fractionation; D003545:Cysteine / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure*; D029968:Escherichia coli Proteins; D019204:GTP-Binding Proteins / Q000378:metabolism; D005798:Genes, Bacterial; D006602:Hexosyltransferases / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D009097:Multienzyme Complexes / Q000378:metabolism; D002267:Muramoylpentapeptide Carboxypeptidase; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan / Q000096:biosynthesis*; D046928:Peptidoglycan Glycosyltransferase; D010458:Peptidyl Transferases / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C065103:FtsA protein, Bacteria; C489310:FtsA protein, E coli; C478704:FtsI protein, E coli; C068023:FtsQ protein, E coli; C071525:FtsZ protein, Bacteria; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D046928:Peptidoglycan Glycosyltransferase; D002267:Muramoylpentapeptide Carboxypeptidase; D019204:GTP-Binding Proteins; D003545:Cysteine