821P: THREE-DIMENSIONAL STRUCTURES AND PROPERTIES OF A TRANSFORMING AND A NONTRANSFORMING GLYCINE-12 MUTANT OF P21H-RAS

Citation:
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.
PDB ID: 821PDownload
MMDB ID: 58596
PDB Deposition Date: 1993/3/29
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 1.5  Å
Source Organism:
Similar Structures:
Biological Unit for 821P: dimeric; determined by author
Molecular Components in 821P
Label Count Molecule
Proteins (2 molecules)
2
C-h-ras P21 Protein(Gene symbol: HRAS)
Molecule annotation
Chemicals (4 molecules)
1
2
2
2
* Click molecule labels to explore molecular sequence information.

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