title: Influence of the yjiL-mdtM Gene Cluster on the Antibacterial Activity of Proline-Rich Antimicrobial Peptides Overcoming Escherichia coli Resistance Induced by the Missing SbmA Transporter System.
abstract: In view of increasing health threats from multiresistant pathogens, antimicrobial peptides (AMPs) and, specifically, proline-rich AMPs (PrAMPs) have been investigated in animal models. PrAMPs enter bacteria via the ABC transporter SbmA and inhibit intracellular targets. We used phage transduction (Tn10 insertion) to screen by random mutagenesis for alternative uptake mechanisms for analogs of apidaecin 1b, a honeybee-derived PrAMP. All 24 apidaecin-resistant mutants had the Tn10 insertion in the sbmA gene. These sbmA::Tn10 insertion mutants and the Escherichia coli BW25113 ΔsbmA (JW0368) strain were still susceptible to the bactenecin PrAMP Bac7(1-35) and oncocin PrAMPs Onc18 and Onc112, as well as to Chex1-Arg20, despite significantly reduced internalizations. In a second round of random mutagenesis, the remaining susceptibility was linked to the yjiL-mdtM gene cluster. E. coli BW25113 and its ΔyjiL null mutant (JW5785) were equally susceptible to all PrAMPs tested, whereas the BW25113 ΔmdtM mutant was less susceptible to oncocins. The JW0368 yjiL::Tn10 transposon mutant (BS2) was resistant to all short PrAMPs and susceptible only to full-length Bac7 and A3-APO. Interestingly, PrAMPs appear to enter bacteria via MdtM, a multidrug resistance transporter (drug/H(+) antiporter) of the major facilitator superfamily (MFS) that can efflux antibiotics, biocides, and bile salts. In conclusion, PrAMPs enter bacteria via ABC and MFS transporters that efflux antibiotics and cytotoxic compounds from the cytoplasm to the periplasm.
authors.affiliation: Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Leipzig, Germany Center for Biotechnology and Biomedicine, Universität Leipzig, Leipzig, Germany.
authors.forename: Andor
authors.initials: A
authors.lastname: Krizsan
authors.affiliation: Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Leipzig, Germany Center for Biotechnology and Biomedicine, Universität Leipzig, Leipzig, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Knappe
authors.affiliation: Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Leipzig, Germany Center for Biotechnology and Biomedicine, Universität Leipzig, Leipzig, Germany hoffmann@chemie.uni-leipzig.de.
authors.forename: Ralf
authors.initials: R
authors.lastname: Hoffmann
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000302:isolation & purification / Q000494:pharmacology*; D017920:Antiporters / Q000235:genetics* / Q000378:metabolism; D001516:Bees / Q000737:chemistry / Q000502:physiology; D001692:Biological Transport; D003090:Coliphages / Q000235:genetics; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial / Q000187:drug effects* / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D026901:Membrane Transport Proteins / Q000172:deficiency / Q000235:genetics*; D005810:Multigene Family; D009154:Mutation; D010456:Peptides, Cyclic / Q000302:isolation & purification / Q000494:pharmacology; D019897:Periplasm / Q000187:drug effects / Q000378:metabolism; D055232:Proline-Rich Protein Domains; D014161:Transduction, Genetic
chemical_list: D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D017920:Antiporters; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; C574623:MdtM protein, E coli; D026901:Membrane Transport Proteins; D010456:Peptides, Cyclic; C529573:SbmA protein, E coli; C551620:oncocin; C056454:bactenecin; C061361:apidaecin