title: Import of periplasmic bacteriocins targeting the murein.
abstract: Colicins are the only proteins imported by Escherichia coli and thus serve as tools to study the protein import mechanism. Most of the colicins studied degrade DNA, 16S RNA or tRNA in the cytoplasm, or form pores in the cytoplasmic membrane. Two bacteriocins, Cma (colicin M) and Pst (pesticin), affect the murein structure in the periplasm. These two bacteriocins must be imported only across the outer membrane and therefore represent the simplest system for studying protein import. Cma can be reversibly translocated across the outer membrane. Cma and Pst unfold during import. The crystal structure of Pst reveals a phage T4L (T4 lysozyme) fold of the activity domain. Both bacteriocins require energy for import which is translocated from the cytoplasmic membrane into the outer membrane by the Ton system. Cma kills cells only when the periplasmic FkpA PPIase (peptidylprolyl cis-trans isomerase)/chaperone is present.
authors.affiliation: Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany. volkmar.braun@tuebingen.mpg.de
authors.forename: Volkmar
authors.initials: V
authors.lastname: Braun
authors.forename: Stephanie
authors.initials: S
authors.lastname: Helbig
authors.forename: Silke I
authors.initials: SI
authors.lastname: Patzer
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001430:Bacteriocins / Q000737:chemistry / Q000378:metabolism*; D003087:Colicins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology; D008958:Models, Molecular; D010457:Peptidoglycan / Q000378:metabolism*; D019696:Peptidylprolyl Isomerase / Q000378:metabolism / Q000502:physiology; D033903:Periplasmic Proteins / Q000378:metabolism / Q000502:physiology; D011487:Protein Conformation; D021381:Protein Transport
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D003087:Colicins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D010457:Peptidoglycan; D033903:Periplasmic Proteins; C011330:Pesticin; D019696:Peptidylprolyl Isomerase; C068254:FkpA protein, E coli