title: Membrane interactions of phylloseptin-1, -2, and -3 peptides by oriented solid-state NMR spectroscopy.
abstract: Phylloseptin-1, -2, and -3 are three members of the family of linear cationic antimicrobial peptides found in tree frogs. The highly homologous peptides encompass 19 amino acids, and only differ in the amino acid composition and charge at the six most carboxy-terminal residues. Here, we investigated how such subtle changes are reflected in their membrane interactions and how these can be correlated to their biological activities. To this end, the three peptides were labeled with stable isotopes, reconstituted into oriented phospholipid bilayers, and their detailed topology determined by a combined approach using (2)H and (15)N solid-state NMR spectroscopy. Although phylloseptin-2 and -3 adopt perfect in-plane alignments, the tilt angle of phylloseptin-1 deviates by 8° probably to assure a more water exposed localization of the lysine-17 side chain. Furthermore, different azimuthal angles are observed, positioning the amphipathic helices of all three peptides with the charged residues well exposed to the water phase. Interestingly, our studies also reveal that two orientation-dependent (2)H quadrupolar splittings from methyl-deuterated alanines and one (15)N amide chemical shift are sufficient to unambiguously determine the topology of phylloseptin-1, where quadrupolar splittings close to the maximum impose the most stringent angular restraints. As a result of these studies, a strategy is proposed where the topology of a peptide structure can be determined accurately from the labeling with (15)N and (2)H isotopes of only a few amino acid residues.
authors.affiliation: Universidade Federal de Minas Gerais, Departamento de Química, Belo Horizonte, MG, Brazil; Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France.
authors.forename: Jarbas M
authors.initials: JM
authors.lastname: Resende
authors.affiliation: Universidade Federal de Minas Gerais, Departamento de Química, Belo Horizonte, MG, Brazil; Universidade Federal do Vales do Jequitinhonha e Mucuri, Diamantina, MG, Brazil.
authors.forename: Rodrigo M
authors.initials: RM
authors.lastname: Verly
authors.affiliation: Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France.
authors.forename: Christopher
authors.initials: C
authors.lastname: Aisenbrey
authors.affiliation: Universidade Federal de Minas Gerais, Departamento de Química, Belo Horizonte, MG, Brazil.
authors.forename: Amary
authors.initials: A
authors.lastname: Cesar
authors.affiliation: Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bertani
authors.affiliation: Universidade Federal de Minas Gerais, Departamento de Química, Belo Horizonte, MG, Brazil.
authors.forename: Dorila
authors.initials: D
authors.lastname: Piló-Veloso
authors.affiliation: Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France. Electronic address: bechinge@unistra.fr.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Bechinger
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000737:chemistry*; D003198:Computer Simulation; D003903:Deuterium / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D009590:Nitrogen Radioisotopes / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry
chemical_list: D023181:Antimicrobial Cationic Peptides; D008051:Lipid Bilayers; D009590:Nitrogen Radioisotopes; D010743:Phospholipids; C533251:phylloseptin-1, Phyllomedusa; C533252:phylloseptin-2, Phyllomedusa; C533253:phylloseptin-3, Phyllomedusa; D003903:Deuterium