title: A conformational rearrangement in gramicidin A: from a double-stranded left-handed to a single-stranded right-handed helix.
abstract: A conformational transition is described for the polypeptide, gramicidin A, in which a dimer that forms a left-handed intertwined antiparallel helix is converted to a single-stranded amino terminus to amino terminus right-handed helix. The starting structure is determined here by solution NMR methods while reference is made to the well-established folding motif of gramicidin in a lipid bilayer for the ultimate conformation of this transition. Furthermore, an organic solvent system of benzene and ethanol in which gramicidin has a unique conformation is identified. This conformation is shown to be very similar to that derived from X-ray diffraction of crystals prepared from a similar solvent system.
authors.affiliation: Department of Chemistry, Florida State University, Tallahassee 32306-3006.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang
authors.forename: S M
authors.initials: SM
authors.lastname: Pascal
authors.forename: T A
authors.initials: TA
authors.lastname: Cross
mesh_terms: D000595:Amino Acid Sequence; D001554:Benzene / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D006096:Gramicidin / Q000737:chemistry*; D006860:Hydrogen Bonding; D007473:Ion Channels / Q000737:chemistry*; D008051:Lipid Bilayers; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012996:Solutions; D012997:Solvents
chemical_list: D007473:Ion Channels; D008051:Lipid Bilayers; D012996:Solutions; D012997:Solvents; D006096:Gramicidin; D000431:Ethanol; D001554:Benzene