title: Three-dimensional structure of a genetically engineered variant of porcine growth hormone.
abstract: The three-dimensional structure of a genetically engineered variant of porcine growth hormone, methionyl porcine somatotropin (MPS), has been determined at 2.8-A resolution, using single crystal x-ray diffraction techniques. Phases were obtained by use of a single isomorphous K2OsCl6 derivative and were improved by use of the density modification procedure. The MPS structure is predominantly helical. It consists mainly of four antiparallel alpha-helices arranged in a left twisted helical bundle, a structural motif observed in a number of other unrelated proteins. However, the way the four helices are connected in the bundle is unusual and, to our knowledge, has never been reported before. Alignment of the amino acid sequence of MPS with that of other growth hormones reveals that residues within the alpha-helices are predominantly invariant and thus these invariant residues are necessary to maintain the structural integrity of these proteins.
authors.forename: S S
authors.initials: SS
authors.lastname: Abdel-Meguid
authors.forename: H S
authors.initials: HS
authors.lastname: Shieh
authors.forename: W W
authors.initials: WW
authors.lastname: Smith
authors.forename: H E
authors.initials: HE
authors.lastname: Dayringer
authors.forename: B N
authors.initials: BN
authors.lastname: Violand
authors.forename: L A
authors.initials: LA
authors.lastname: Bentle
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003198:Computer Simulation; D003461:Crystallography; D003573:Cytochrome b Group; D003574:Cytochrome c Group; D029968:Escherichia coli Proteins; D013006:Growth Hormone; D006422:Hemerythrin / Q000031:analogs & derivatives; D011487:Protein Conformation; D011994:Recombinant Proteins; D014961:X-Ray Diffraction
chemical_list: D003573:Cytochrome b Group; D003574:Cytochrome c Group; D029968:Escherichia coli Proteins; D006422:Hemerythrin; D011994:Recombinant Proteins; C008571:myohemerythrin; D013006:Growth Hormone; C017850:cytochrome b562, E coli