title: How many antimicrobial peptide molecules kill a bacterium? The case of PMAP-23.
abstract: Antimicrobial peptides (AMPs) kill bacteria mainly through the perturbation of their membranes and are promising compounds to fight drug resistance. Models of the mechanism of AMPs-induced membrane perturbation were developed based on experiments in liposomes, but their relevance for bacterial killing is debated. We determined the association of an analogue of the AMP PMAP-23 to Escherichia coli cells, under the same experimental conditions used to measure bactericidal activity. Killing took place only when bound peptides completely saturated bacterial membranes (10(6)-10(7) bound peptides per cell), indicating that the "carpet" model for the perturbation of artificial bilayers is representative of what happens in real bacteria. This finding supports the view that, at least for this peptide, a microbicidal mechanism is possible in vivo only at micromolar total peptide concentrations. We also showed that, notwithstanding their simplicity, liposomes represent a reliable model to characterize AMPs partition in bacterial membranes.
authors: Department of Chemical Sciences and Technologies, University of Rome Tor Vergata , 00133 Rome, Italy.
authors: Daniela
authors: D
authors: Roversi
authors: Vincenzo
authors: V
authors: Luca
authors: Simone
authors: S
authors: Aureli
authors: Yoonkyung
authors: Y
authors: Park
authors: Maria Luisa
authors: ML
authors: Mangoni
authors: Lorenzo
authors: L
authors: Stella
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004926:Escherichia coli / Q000187:drug effects*; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D008055:Lipids; D008081:Liposomes; C086301:porcine myeloid antibacterial peptide 23