title: Structure of tightly membrane-bound mastoparan-X, a G-protein-activating peptide, determined by solid-state NMR.
abstract: The structure of mastoparan-X (MP-X), a G-protein activating peptide from wasp venom, in the state tightly bound to anionic phospholipid bilayers was determined by solid-state NMR spectroscopy. Carbon-13 and nitrogen-15 NMR signals of uniformly labeled MP-X were completely assigned by multidimensional intraresidue C-C, N-CalphaCbeta, and N-Calpha-C', and interresidue Calpha-CalphaCbeta, N-CalphaCbeta, and N-C'-Calpha correlation experiments. The backbone torsion angles were predicted from the chemical shifts of 13C', 13Calpha, 13Cbeta, and 15N signals with the aid of protein NMR database programs. In addition, two 13C-13C and three 13C-15N distances between backbone nuclei were precisely measured by rotational resonance and REDOR experiments, respectively. The backbone structure of MP-X was determined from the 26 dihedral angle restraints and five distances with an average root-mean-square deviation of 0.6 A. Peptide MP-X in the bilayer-bound state formed an amphiphilic alpha-helix for residues Trp3-Leu14 and adopted an extended conformation for Asn2. This membrane-bound conformation is discussed in relation to the peptide's activities to form pores in membranes and to activate G-proteins. This study demonstrates the power of multidimensional solid-state NMR of uniformly isotope-labeled molecules and distance measurements for determining the structures of peptides bound to lipid membranes.
authors.affiliation: Institute for Protein Research, Osaka University, Suita, Japan.
authors.forename: Yasuto
authors.initials: Y
authors.lastname: Todokoro
authors.forename: Ikuko
authors.initials: I
authors.lastname: Yumen
authors.forename: Kei
authors.initials: K
authors.lastname: Fukushima
authors.forename: Shin-Won
authors.initials: SW
authors.lastname: Kang
authors.forename: Jang-Su
authors.initials: JS
authors.lastname: Park
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kohno
authors.forename: Kaori
authors.initials: K
authors.lastname: Wakamatsu
authors.forename: Hideo
authors.initials: H
authors.lastname: Akutsu
authors.forename: Toshimichi
authors.initials: T
authors.lastname: Fujiwara
mesh_terms: D019204:GTP-Binding Proteins / Q000737:chemistry*; D036341:Intercellular Signaling Peptides and Proteins; D008051:Lipid Bilayers / Q000032:analysis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008560:Membrane Fluidity; D008565:Membrane Proteins / Q000032:analysis / Q000737:chemistry*; D010455:Peptides / Q000032:analysis / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D008051:Lipid Bilayers; D008565:Membrane Proteins; D010455:Peptides; C071123:mastoparan X; D019204:GTP-Binding Proteins