'''Crystal structure of M-Ras in complex with GppNHp'''
===Crystal structure of M-Ras in complex with GppNHp===
==Overview==
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Although some members of Ras family small GTPases, including M-Ras, share the primary structure of their effector regions with Ras, they exhibit vastly different binding properties to Ras effectors such as c-Raf-1. We have solved the crystal structure of M-Ras in the GDP-bound and guanosine 5'-(beta,gamma-imido)triphosphate (Gpp(NH)p)-bound forms. The overall structure of M-Ras resembles those of H-Ras and Rap2A, except that M-Ras-Gpp(NH)p exhibits a distinctive switch I conformation, which is caused by impaired intramolecular interactions between Thr-45 (corresponding to Thr-35 of H-Ras) of the effector region and the gamma-phosphate of Gpp(NH)p. Previous 31P NMR studies showed that H-Ras-Gpp(NH)p exists in two interconverting conformations, states 1 and 2. Whereas state 2 is a predominant form of H-Ras and corresponds to the "on" conformation found in the complex with effectors, state 1 is thought to represent the "off" conformation, whose tertiary structure remains unknown. 31P NMR analysis shows that free M-Ras-Gpp(NH)p predominantly assumes the state 1 conformation, which undergoes conformational transition to state 2 upon association with c-Raf-1. These results indicate that the solved structure of M-Ras-Gp-p(NH)p corresponds to the state 1 conformation. The predominance of state 1 in M-Ras is likely to account for its weak binding ability to the Ras effectors, suggesting the importance of the tertiary structure factor in small GTPase-effector interaction. Further, the first determination of the state 1 structure provides a molecular basis for developing novel anti-cancer drugs as compounds that hold Ras in the state 1 "off" conformation.
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==About this Structure==
==About this Structure==
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[[Category: Ye, M.]]
[[Category: Ye, M.]]
[[Category: Gtp-binding]]
[[Category: Gtp-binding]]
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Revision as of 16:31, 29 July 2008
This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.
1X1S is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of M-Ras reveals a GTP-bound "off" state conformation of Ras family small GTPases., Ye M, Shima F, Muraoka S, Liao J, Okamoto H, Yamamoto M, Tamura A, Yagi N, Ueki T, Kataoka T, J Biol Chem. 2005 Sep 2;280(35):31267-75. Epub 2005 Jun 30. PMID:15994326
