Download MendeleyThree-dimensional structures and properties of a transforming and a nontransforming glycine-12 mutant of p21H-ras.
Franken, S.M., Scheidig, A.J., Krengel, U., Rensland, H., Lautwein, A., Geyer, M., Scheffzek, K., Goody, R.S., Kalbitzer, H.R., Pai, E.F., Wittinghofer, A.(1993) Biochemistry 32: 8411-8420
- PubMed: 8357792
- DOI: https://doi.org/10.1021/bi00084a005
- Primary Citation of Related Structures:
1AGP, 821P - PubMed Abstract:
The three-dimensional structures and biochemical properties of two mutants of the G-domain (residues 1-166) of p21H-ras, p21 (G12D) and p21 (G12P), have been determined in the triphosphate-bound form using guanosine 5'-(beta,gamma-imido)triphosphate (GppNHp). They correspond to the most frequent oncogenic and the only nononcogenic mutation of Gly-12, respectively. The G12D mutation is the only mutant analyzed so far that crystallizes in a space group different from wild type, and the atomic model of the protein shows the most drastic changes of structure around the active site as compared to wild-type p21. This is due to the interactions of the aspartic acid side chain with Tyr-32, Gln-61, and the gamma-phosphate, which result in reduced mobility of these structural elements. The interaction between the carboxylate group of Asp-12 and the gamma-phosphate is mediated by a shared proton, which we show by 31P NMR measurements to exist in solution as well. The structure of p21 (G12P) is remarkably similar to that of wild-type p21 in the active site, including the position of the nucleophilic water. The pyrrolidine ring of Pro-12 points outward and seems to be responsible for the weaker affinity toward GAP (GTPase-activating protein) and the failure of GAP to stimulate GTP hydrolysis.
Organizational Affiliation:
Abteilung Biophysik, Max-Planck-Institut für Medizinische Forschung, Heidelberg, Germany.
