title: The defensin-lipid interaction: insights on the binding states of the human antimicrobial peptide HNP-1 to model bacterial membranes.
abstract: Antimicrobial peptides are an important component of innate immunity and have generated considerable interest as a new potential class of natural antibiotics. The biological activity of antimicrobial peptides is strongly influenced by peptide-membrane interactions. Human Neutrophil Peptide 1 (HNP-1) is a 30 aminoacid peptide, belonging to the class of α-defensins. Many biophysical studies have been performed on this peptide to define its mechanism of action. Combining spectroscopic and thermodynamic analysis, insights on the interaction of the α-defensin with POPE:POPG:CL negative charged bilayers are given. The binding states of the peptide below and above the threshold concentration have been analyzed showing that the interaction with lipid bilayers is dependent by peptide concentration. These novel results that indicate how affinity and biological activities of natural antibiotics are depending by their concentration, might open new way of investigation of the antimicrobial mode of action.
authors.affiliation: Department of Chemistry, University of Siena, 53100 Siena, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Bonucci
authors.forename: Enrico
authors.initials: E
authors.lastname: Balducci
authors.forename: Sara
authors.initials: S
authors.lastname: Pistolesi
authors.forename: Rebecca
authors.initials: R
authors.lastname: Pogni
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry; D018407:Bacterial Physiological Phenomena; D001703:Biophysics / Q000379:methods; D002412:Cations; D002462:Cell Membrane / Q000378:metabolism*; D002942:Circular Dichroism; D023082:Defensins / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry; D008055:Lipids / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000379:methods; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry; D023084:alpha-Defensins / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D002412:Cations; D023082:Defensins; D008051:Lipid Bilayers; D008055:Lipids; D010455:Peptides; D023084:alpha-Defensins; C406413:human neutrophil peptide 1; D014364:Tryptophan