title: Membrane interactions and dynamics of a 21-mer cytotoxic peptide: a solid-state NMR study.
abstract: We have investigated the membrane interactions and dynamics of a 21-mer cytotoxic model peptide that acts as an ion channel by solid-state NMR spectroscopy. To shed light on its mechanism of membrane perturbation, (31)P and (2)H NMR experiments were performed on 21-mer peptide-containing bicelles. (31)P NMR results indicate that the 21-mer peptide stabilizes the bicelle structure and orientation in the magnetic field and perturbs the lipid polar head group conformation. On the other hand, (2)H NMR spectra reveal that the 21-mer peptide orders the lipid acyl chains upon binding. (15)N NMR experiments performed in DMPC bilayers stacked between glass plates also reveal that the 21-mer peptide remains at the bilayer surface. (15)N NMR experiments in perpendicular DMPC bicelles indicate that the 21-mer peptide does not show a circular orientational distribution in the bicelle planar region. Finally, (13)C NMR experiments were used to study the 21-mer peptide dynamics in DMPC multilamellar vesicles. By analyzing the (13)CO spinning sidebands, the results show that the 21-mer peptide is immobilized upon membrane binding. In light of these results, we propose a model of membrane interaction for the 21-mer peptide where it lies at the bilayer surface and perturbs the lipid head group conformation.
authors.affiliation: Département de Chimie, PROTEO (Regroupement Québécois de Recherche sur la Fonction, la Structure et l'Ingénierie des Protéines), CERMA (Centre de Recherche sur les Matériaux Avancés), Université Laval, Québec, Québec, Canada G1V 0A6.
authors.forename: Marise
authors.initials: M
authors.lastname: Ouellet
authors.forename: Normand
authors.initials: N
authors.lastname: Voyer
authors.forename: Michèle
authors.initials: M
authors.lastname: Auger
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D003603:Cytotoxins / Q000138:chemical synthesis / Q000737:chemistry*; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular
chemical_list: D023181:Antimicrobial Cationic Peptides; D003603:Cytotoxins; D008051:Lipid Bilayers; D004134:Dimyristoylphosphatidylcholine