title: Peptide-related alterations of membrane-associated water: deuterium solid-state NMR investigations of phosphatidylcholine membranes at different hydration levels.
abstract: Deuterated water associated with oriented POPC bilayers was investigated before and after the addition of 2 mol% peptide. Membranes in the presences of antimicrobial-(LAH4), pore-forming- (the segments M2 of influenza A and S4 of the domain I of rat brain sodium channels) or lysine-containing model peptides (LAK1 and LAK3) were investigated by (2)H and proton-decoupled (31)P solid-state NMR. The NMR spectra were recorded as a function of hydration in the range between 15 and 93% relative humidity and of sample composition. In the presence of peptides an increased association of water is observed. A quantitative analysis suggests that the peptide-induced changes in the lipid bilayer packing have a significant effect on membrane-water association. The quadrupolar splittings of (2)H(2)O at a given degree of hydration indicate that the changes of the water deuterium order parameter are specific for the peptide sequence and the lipid composition.
authors.affiliation: Faculté de Chimie, Institut le Bel, 4 rue Blaise Pascal, 67070 Strasbourg, France.
authors.forename: Cléria Mendonça
authors.initials: CM
authors.lastname: Moraes
authors.forename: Burkhard
authors.initials: B
authors.lastname: Bechinger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000502:physiology; D003903:Deuterium; D008081:Liposomes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008567:Membranes, Artificial; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D011487:Protein Conformation; D051381:Rats; D015222:Sodium Channels / Q000737:chemistry / Q000502:physiology; D014867:Water
chemical_list: D008081:Liposomes; D008567:Membranes, Artificial; D009419:Nerve Tissue Proteins; D010455:Peptides; D010713:Phosphatidylcholines; D015222:Sodium Channels; D014867:Water; D003903:Deuterium; C028694:1-palmitoyl-2-oleoylphosphatidylcholine