title: In vitro synthesis of cross-linked murein and its attachment to sacculi by PBP1A from Escherichia coli.
abstract: The penicillin-binding protein (PBP) 1A is a major murein (peptidoglycan) synthase in Escherichia coli. The murein synthesis activity of PBP1A was studied in vitro with radioactive lipid II substrate. PBP1A produced murein glycan strands by transglycosylation and formed peptide cross-links by transpeptidation. Time course experiments revealed that PBP1A, unlike PBP1B, required the presence of polymerized glycan strands carrying monomeric peptides for cross-linking activity. PBP1A was capable of attaching nascent murein synthesized from radioactive lipid II to nonlabeled murein sacculi. The attachment of the new material occurred by transpeptidation reactions in which monomeric triand tetrapeptides in the sacculi were the acceptors.
authors.affiliation: Mikrobielle Genetik, Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Born
authors.forename: Eefjan
authors.initials: E
authors.lastname: Breukink
authors.forename: Waldemar
authors.initials: W
authors.lastname: Vollmer
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D002384:Catalysis; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism*; D066298:In Vitro Techniques; D008956:Models, Chemical; D008969:Molecular Sequence Data; D046915:Penicillin-Binding Proteins / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D010457:Peptidoglycan / Q000096:biosynthesis / Q000737:chemistry*; D010458:Peptidyl Transferases / Q000737:chemistry; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D046915:Penicillin-Binding Proteins; D010455:Peptides; D010457:Peptidoglycan; D010458:Peptidyl Transferases