title: Identification and characterization of microcin S, a new antibacterial peptide produced by probiotic Escherichia coli G3/10.
abstract: Escherichia coli G3/10 is a component of the probiotic drug Symbioflor 2. In an in vitro assay with human intestinal epithelial cells, E. coli G3/10 is capable of suppressing adherence of enteropathogenic E. coli E2348/69. In this study, we demonstrate that a completely novel class II microcin, produced by probiotic E. coli G3/10, is responsible for this behavior. We named this antibacterial peptide microcin S (MccS). Microcin S is coded on a 50.6 kb megaplasmid of E. coli G3/10, which we have completely sequenced and annotated. The microcin S operon is about 4.7 kb in size and is comprised of four genes. Subcloning of the genes and gene fragments followed by gene expression experiments enabled us to functionally characterize all members of this operon, and to clearly identify the nucleotide sequences encoding the microcin itself (mcsS), its transport apparatus and the gene mcsI conferring self immunity against microcin S. Overexpression of cloned mcsI antagonizes MccS activity, thus protecting indicator strain E. coli E2348/69 in the in vitro adherence assay. Moreover, growth of E. coli transformed with a plasmid containing mcsS under control of an araC PBAD activator-promoter is inhibited upon mcsS induction. Our data provide further mechanistic insight into the probiotic behavior of E. coli G3/10.
authors.affiliation: Institute of Medical Microbiology and Hygiene, TU Dresden, Dresden, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Zschüttig
authors.forename: Kurt
authors.initials: K
authors.lastname: Zimmermann
authors.forename: Jochen
authors.initials: J
authors.lastname: Blom
authors.forename: Alexander
authors.initials: A
authors.lastname: Goesmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Pöhlmann
authors.forename: Florian
authors.initials: F
authors.lastname: Gunzer
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000235:genetics; D001430:Bacteriocins / Q000235:genetics / Q000378:metabolism*; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order; D006801:Humans; D050296:Microbial Viability / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009876:Operon / Q000235:genetics; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D019936:Probiotics / Q000378:metabolism*; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D010455:Peptides; C020411:microcin