title: Conformation change of effector-region residues in antiparallel beta-sheet of human c-Ha-ras protein on GDP----GTP gamma S exchange: a two-dimensional NMR study.
abstract: The conformations of a truncated human c-Ha-ras gene product [ras(1-171) protein] in the GDP-bound form and in the GTP gamma S-bound form were compared by two-dimensional nuclear Overhauser effect spectroscopy (NOESY). As for the GDP-bound ras(1-171) protein, three NOESY cross peaks were observed in the region of 4.5-6.0 ppm, indicating a regular antiparallel beta-sheet structure. On the ligand exchange from GDP to GTP gamma S, one of the three NOESY cross peaks disappeared and the other two cross peaks were appreciably shifted. By analysis of the effects of specific deuteration of leucine residues and the homonuclear Hartmann-Hahn spectroscopy, the antiparallel beta-sheet was found to consist of residues 38-44 and residues 51-57. The conformations around Ser-39 and Leu-56 are of the regular antiparallel beta-strand type in the GDP-bound state, and largely distorted in the GTP gamma S-bound state, which is probably related to the conformational activation of the effector region of ras proteins by ligand exchange from GDP to GTP gamma S.
authors.affiliation: Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamasaki
authors.forename: G
authors.initials: G
authors.lastname: Kawai
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
authors.forename: Y
authors.initials: Y
authors.lastname: Muto
authors.forename: J
authors.initials: J
authors.lastname: Fujita
authors.forename: T
authors.initials: T
authors.lastname: Miyazawa
authors.forename: S
authors.initials: S
authors.lastname: Nishimura
authors.forename: S
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D000595:Amino Acid Sequence; D003903:Deuterium; D006150:Guanine Nucleotides / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006153:Guanosine Diphosphate / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins / Q000378:metabolism / Q000648:ultrastructure*; D016283:Proto-Oncogene Proteins p21(ras); D013873:Thionucleotides / Q000378:metabolism*
chemical_list: D006150:Guanine Nucleotides; D011518:Proto-Oncogene Proteins; D013873:Thionucleotides; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D003903:Deuterium; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)