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New page: left|200px<br /><applet load="2rgb" size="350" color="white" frame="true" align="right" spinBox="true" caption="2rgb, resolution 1.35Å" /> '''Crystal structure of...
 
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==Overview==
==Overview==
Transformation efficiencies of Ras mutants at residue 61 range over three, orders of magnitude, but the in vitro GTPase activity decreases 10-fold, for all mutants. We show that Raf impairs the GTPase activity of RasQ61L, suggesting that the Ras/Raf complex differentially modulates, transformation. Our crystal structures show that, in transforming mutants, switch II takes part in a network of hydrophobic interactions burying the, nucleotide and precatalytic water molecule. Our results suggest that Y32, and a water molecule bridging it to the gamma-phosphate in the wild-type, structure play a role in GTP hydrolysis in lieu of the Arg finger in the, absence of GAP. The bridging water molecule is absent in the transforming, mutants, contributing to the burying of the nucleotide. We propose a, mechanism for intrinsic hydrolysis in Raf-bound Ras and elucidate, structural features in the Q61 mutants that correlate with their potency, to transform cells.
Transformation efficiencies of Ras mutants at residue 61 range over three orders of magnitude, but the in vitro GTPase activity decreases 10-fold for all mutants. We show that Raf impairs the GTPase activity of RasQ61L, suggesting that the Ras/Raf complex differentially modulates transformation. Our crystal structures show that, in transforming mutants, switch II takes part in a network of hydrophobic interactions burying the nucleotide and precatalytic water molecule. Our results suggest that Y32 and a water molecule bridging it to the gamma-phosphate in the wild-type structure play a role in GTP hydrolysis in lieu of the Arg finger in the absence of GAP. The bridging water molecule is absent in the transforming mutants, contributing to the burying of the nucleotide. We propose a mechanism for intrinsic hydrolysis in Raf-bound Ras and elucidate structural features in the Q61 mutants that correlate with their potency to transform cells.


==About this Structure==
==About this Structure==
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==Reference==
==Reference==
Transformation Efficiency of RasQ61 Mutants Linked to Structural Features of the Switch Regions in the Presence of Raf., Buhrman G, Wink G, Mattos C, Structure. 2007 Dec;15(12):1618-29. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18073111 18073111]
Transformation efficiency of RasQ61 mutants linked to structural features of the switch regions in the presence of Raf., Buhrman G, Wink G, Mattos C, Structure. 2007 Dec;15(12):1618-29. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18073111 18073111]
[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
[[Category: Single protein]]
[[Category: Single protein]]
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[[Category: signaling protein]]
[[Category: signaling protein]]


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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:47:02 2008''

Revision as of 19:47, 21 February 2008

File:2rgb.jpg


2rgb, resolution 1.35Å

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Crystal structure of H-RasQ61K-GppNHp

OverviewOverview

Transformation efficiencies of Ras mutants at residue 61 range over three orders of magnitude, but the in vitro GTPase activity decreases 10-fold for all mutants. We show that Raf impairs the GTPase activity of RasQ61L, suggesting that the Ras/Raf complex differentially modulates transformation. Our crystal structures show that, in transforming mutants, switch II takes part in a network of hydrophobic interactions burying the nucleotide and precatalytic water molecule. Our results suggest that Y32 and a water molecule bridging it to the gamma-phosphate in the wild-type structure play a role in GTP hydrolysis in lieu of the Arg finger in the absence of GAP. The bridging water molecule is absent in the transforming mutants, contributing to the burying of the nucleotide. We propose a mechanism for intrinsic hydrolysis in Raf-bound Ras and elucidate structural features in the Q61 mutants that correlate with their potency to transform cells.

About this StructureAbout this Structure

2RGB is a Single protein structure of sequence from Homo sapiens with , and as ligands. Full crystallographic information is available from OCA.

ReferenceReference

Transformation efficiency of RasQ61 mutants linked to structural features of the switch regions in the presence of Raf., Buhrman G, Wink G, Mattos C, Structure. 2007 Dec;15(12):1618-29. PMID:18073111

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