2q21
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CRYSTAL STRUCTURES AT 2.2 ANGSTROMS RESOLUTION OF THE CATALYTIC DOMAINS OF NORMAL RAS PROTEIN AND AN ONCOGENIC MUTANT COMPLEXED WITH GSP
OverviewOverview
The biological functions of ras proteins are controlled by the bound, guanine nucleotide GDP or GTP. The GTP-bound conformation is biologically, active, and is rapidly deactivated to the GDP-bound conformation through, interaction with GAP (GTPase Activating Protein). Most transforming, mutants of ras proteins have drastically reduced GTP hydrolysis rates even, in the presence of GAP. The crystal structures of the GDP complexes of ras, proteins at 2.2 A resolution reveal the detailed interaction between the, ras proteins and the GDP molecule. All the currently known transforming, mutation positions are clustered around the bound guanine nucleotide, molecule. The presumed "effector" region and the GAP recognition region, are both highly exposed. No significant structural differences were found, between the GDP complexes of normal ras protein and the oncogenic mutant, with valine at position 12, except the side-chain of the valine residue., However, comparison with GTP-analog complexes of ras proteins suggests, that the valine side-chain may inhibit GTP hydrolysis in two possible, ways: (1) interacting directly with the gamma-phosphate and altering its, orientation or the conformation of protein residues around the phosphates;, and/or (2) preventing either the departure of gamma-phosphate on GTP, hydrolysis or the entrance of a nucleophilic group to attack the, gamma-phosphate. The structural similarity between ras protein and the, bacterial elongation factor Tu suggests that their common structural motif, might be conserved for other guanine nucleotide binding proteins.
DiseaseDisease
Known diseases associated with this structure: Bladder cancer, somatic OMIM:[190020], Costello syndrome OMIM:[190020], Thyroid carcinoma, follicular, somatic OMIM:[190020]
About this StructureAbout this Structure
2Q21 is a Single protein structure of sequence from Homo sapiens with MG and GDP as ligands. This structure superseeds the now removed PDB entry 3P21. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures at 2.2 A resolution of the catalytic domains of normal ras protein and an oncogenic mutant complexed with GDP., Tong LA, de Vos AM, Milburn MV, Kim SH, J Mol Biol. 1991 Feb 5;217(3):503-16. PMID:1899707
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