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.
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.
Chen
L Q
LQ
Department of Crystallography, University of Pittsburgh, PA 15260.
Rose
J P
JP
Breslow
E
E
Yang
D
D
Chang
W R
WR
Furey
W F
WF
Sax
M
M
Wang
B C
BC
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
D004151:Dipeptides; D004220:Disulfides; D046911:Macromolecular Substances; D009481:Neurophysins; D007455:Iodine