title: High-resolution conformation of gramicidin A in a lipid bilayer by solid-state NMR.
abstract: Solid-state nuclear magnetic resonance spectroscopy of uniformly aligned preparations of gramicidin A in lipid bilayers has been used to elucidate a high-resolution dimeric structure of the cation channel conformation solely on the basis of the amino acid sequence and 144 orientational constraints. This initial structure defines the helical pitch as single-stranded, fixes the number of residues per turn at six to seven, specifies the helix sense as right-handed, and identifies the hydrogen bonds. Refinement of this initial structure yields reasonable hydrogen-bonding distances with only minimal changes in the torsion angles.
authors.affiliation: Institute of Molecular Biophysics, Florida State University, Tallahassee 32306.
authors.forename: R R
authors.initials: RR
authors.lastname: Ketchem
authors.forename: W
authors.initials: W
authors.lastname: Hu
authors.forename: T A
authors.initials: TA
authors.lastname: Cross
mesh_terms: D000595:Amino Acid Sequence; D006096:Gramicidin / Q000737:chemistry*; D006860:Hydrogen Bonding; D008051:Lipid Bilayers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary
chemical_list: D008051:Lipid Bilayers; D006096:Gramicidin