title: Crystal structure of a bovine neurophysin II dipeptide complex at 2.8 A determined from the single-wavelength anomalous scattering signal of an incorporated iodine atom.
abstract: The crystal structure of a dipeptide complex of bovine neurophysin II has been solved at 2.8 A resolution solely by using single-wavelength anomalous scattering data from a single iodinated derivative. The asymmetric unit is an elongated tetramer of dimensions 110 x 40 x 30 A, composed of two dimers related by pseudo twofold symmetry. Each monomer consists of two homologous layers, each with four antiparallel beta-strands. The two regions are connected by a helix followed by a long loop. Monomer-monomer contacts involve antiparallel beta-sheet interactions, which form a dimer with two layers of eight beta-strands. One peptide per monomer occupies the principal hormone-binding pocket formed by part of the amino-terminal region and parts of the connecting helix and loop, with binding to protein consistent with conclusions drawn from solution studies. Dimer-dimer contacts involve the Tyr49 region adjacent to this site. A fifth dipeptide, of unknown biological significance, helps to stabilize one of the monomer-monomer interfaces and the tetramer-tetramer network in the crystal.
authors.affiliation: Department of Crystallography, University of Pittsburgh, PA 15260.
authors.forename: L Q
authors.initials: LQ
authors.lastname: Chen
authors.forename: J P
authors.initials: JP
authors.lastname: Rose
authors.forename: E
authors.initials: E
authors.lastname: Breslow
authors.forename: D
authors.initials: D
authors.lastname: Yang
authors.forename: W R
authors.initials: WR
authors.lastname: Chang
authors.forename: W F
authors.initials: WF
authors.lastname: Furey
authors.forename: M
authors.initials: M
authors.lastname: Sax
authors.forename: B C
authors.initials: BC
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D004151:Dipeptides / Q000737:chemistry*; D004220:Disulfides; D006860:Hydrogen Bonding; D007455:Iodine; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009481:Neurophysins / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D004151:Dipeptides; D004220:Disulfides; D046911:Macromolecular Substances; D009481:Neurophysins; D007455:Iodine