1lf5
Crystal Structure of RasA59G in the GDP-bound Form
Structural highlights
DiseaseRASH_HUMAN Defects in HRAS are the cause of faciocutaneoskeletal syndrome (FCSS) [MIM:218040. A rare condition characterized by prenatally increased growth, postnatal growth deficiency, mental retardation, distinctive facial appearance, cardiovascular abnormalities (typically pulmonic stenosis, hypertrophic cardiomyopathy and/or atrial tachycardia), tumor predisposition, skin and musculoskeletal abnormalities.[1] [2] [3] [4] [5] [6] [7] Defects in HRAS are the cause of congenital myopathy with excess of muscle spindles (CMEMS) [MIM:218040. CMEMS is a variant of Costello syndrome.[8] Defects in HRAS may be a cause of susceptibility to Hurthle cell thyroid carcinoma (HCTC) [MIM:607464. Hurthle cell thyroid carcinoma accounts for approximately 3% of all thyroid cancers. Although they are classified as variants of follicular neoplasms, they are more often multifocal and somewhat more aggressive and are less likely to take up iodine than are other follicular neoplasms. Note=Mutations which change positions 12, 13 or 61 activate the potential of HRAS to transform cultured cells and are implicated in a variety of human tumors. Defects in HRAS are a cause of susceptibility to bladder cancer (BLC) [MIM:109800. A malignancy originating in tissues of the urinary bladder. It often presents with multiple tumors appearing at different times and at different sites in the bladder. Most bladder cancers are transitional cell carcinomas. They begin in cells that normally make up the inner lining of the bladder. Other types of bladder cancer include squamous cell carcinoma (cancer that begins in thin, flat cells) and adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). Bladder cancer is a complex disorder with both genetic and environmental influences. Note=Defects in HRAS are the cause of oral squamous cell carcinoma (OSCC).[9] Defects in HRAS are the cause of Schimmelpenning-Feuerstein-Mims syndrome (SFM) [MIM:163200. A disease characterized by sebaceous nevi, often on the face, associated with variable ipsilateral abnormalities of the central nervous system, ocular anomalies, and skeletal defects. Many oral manifestations have been reported, not only including hypoplastic and malformed teeth, and mucosal papillomatosis, but also ankyloglossia, hemihyperplastic tongue, intraoral nevus, giant cell granuloma, ameloblastoma, bone cysts, follicular cysts, oligodontia, and odontodysplasia. Sebaceous nevi follow the lines of Blaschko and these can continue as linear intraoral lesions, as in mucosal papillomatosis.[10] FunctionRASH_HUMAN Ras proteins bind GDP/GTP and possess intrinsic GTPase activity.[11] [12] [13] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe conformational changes in Ras that accompany the hydrolysis of GTP are critical to its function as a molecular switch in signaling pathways. Understanding how GTP is hydrolyzed by revealing the sequence of intermediary structures in the reaction is essential for understanding Ras signaling. Until now, no structure of an intermediate in GTP hydrolysis has been experimentally determined for Ras alone. We have solved the crystal structure of the Ala-59 to Gly mutant of Ras, (RasA59G), bound to guanosine 5'-imidotriphosphate or GDP to 1.7-A resolution. In the guanosine 5'-imidotriphosphate-bound form, this mutant adopts a conformation that is intermediate between the GTP- and GDP-bound forms of wild-type Ras and that is similar to what has been predicted by molecular dynamics simulation [Ma, J. P. & Karplus, M. (1997) Proc. Natl. Acad. Sci. USA 94, 11905-11910]. This conformation is stabilized by direct and water-mediated interactions between the switch 1 and switch 2 regions and is characterized by an increase in the binding affinity for GTP. We propose that the structural changes promoted by the Ala-59 to Gly mutation exhibit a discrete conformational state assumed by wild-type Ras during GTP hydrolysis. The structural basis for the transition from Ras-GTP to Ras-GDP.,Hall BE, Bar-Sagi D, Nassar N Proc Natl Acad Sci U S A. 2002 Sep 17;99(19):12138-42. Epub 2002 Sep 4. PMID:12213964[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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