Refined crystal structure of the triphosphate conformation of H-ras p21 at 1.35 A resolution: implications for the mechanism of GTP hydrolysis.Pai, E.F., Krengel, U., Petsko, G.A., Goody, R.S., Kabsch, W., Wittinghofer, A.
(1990) EMBO J. 9: 2351-2359
- PubMed: 2196171
- PubMed Abstract:
- Crystallization and Preliminary X-Ray Analysis of the Human C-H-Ras-Oncogene Product P21 Complexed with GTP Analogues
Scherer, A.,John, J.,Linke, R.,Goody, R.S.,Wittinghofer, A.,Pai, E.F.,Holmes, K.C.
(1989) J.Mol.Biol. 206: 257
- Biochemical and Crystallographic Characterization of a Complex of C-Ha-Ras P21 and Caged GTP with Flash Photolysis
Schlichting, I.,Rapp, G.,John, J.,Wittinghofer, A.,Pai, E.F.,Goody, R.S.
(1989) Proc.Natl.Acad.Sci.USA 86: 7687
- Time-Resolved X-Ray Crystallographic Study of the Conformational Change in Ha-Ras P21 Protein on GTP Hydrolysis
Schlichting, I.,Almo, S.C.,Rapp, G.,Wilson, K.,Petratos, K.,Lentfer, A.,Wittinghofer, A.,Kabsch, W.,Pai, E.F.,Petsko, G.A.,Goody, R.S.
(1990) Nature 345: 309
- Structure of the Guanine-Nucleotide-Binding Domain of the Ha-Ras Oncogene Product P21 in the Triphosphate Conformation
Pai, E.F.,Kabsch, W.,Krengel, U.,Holmes, K.C.,John, J.,Wittinghofer, A.
(1989) Nature 341: 209
The crystal structure of the H-ras oncogene protein p21 complexed to the slowly hydrolysing GTP analogue GppNp has been determined at 1.35 A resolution. 211 water molecules have been built into the electron density. The structure has been refined to ...
The crystal structure of the H-ras oncogene protein p21 complexed to the slowly hydrolysing GTP analogue GppNp has been determined at 1.35 A resolution. 211 water molecules have been built into the electron density. The structure has been refined to a final R-factor of 19.8% for all data between 6 A and 1.35 A. The binding sites of the nucleotide and the magnesium ion are revealed in high detail. For the stretch of amino acid residues 61-65, the temperature factors of backbone atoms are four times the average value of 16.1 A2 due to the multiple conformations. In one of these conformations, the side chain of Gln61 makes contact with a water molecule, which is perfectly placed to be the nucleophile attacking the gamma-phosphate of GTP. Based on this observation, we propose a mechanism for GTP hydrolysis involving mainly Gln61 and Glu63 as activating species for in-line attack of water. Nucleophilic displacement is facilitated by hydrogen bonds from residues Thr35, Gly60 and Lys16. A mechanism for rate enhancement by GAP is also proposed.
Max-Planck-Institut für medizinische Forschung, Abteilung Biophysik, Heidelberg, FRG.