Abstract
Crystals of Ha-Ras p21 with caged GTP at the active site have been used to investigate the conformational changes of p21 on GTP hydrolysis. The structure of the short-lived p21.GTP complex was determined by Laue diffraction methods. After GTP hydrolysis, substantial structural changes occur in the parts of the molecule implicated in the interaction with GTPase-activating protein. The trigger for this process seems to be a change in coordination of the active-site Mg2+ ion as a result of loss of the gamma-phosphate of GTP.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Binding Sites
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Chemical Phenomena
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Chemistry, Physical
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Crystallization
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GTP Phosphohydrolases / metabolism
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Guanosine Diphosphate / metabolism
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Guanosine Triphosphate / metabolism*
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Guanylyl Imidodiphosphate / metabolism
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Hydrolysis
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Lysine
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Magnesium / metabolism
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Models, Molecular
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Molecular Structure
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Phosphates / metabolism
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Photolysis
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Protein Conformation
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Proto-Oncogene Proteins / metabolism*
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Proto-Oncogene Proteins p21(ras)
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X-Ray Diffraction*
Substances
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Phosphates
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Proto-Oncogene Proteins
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Guanosine Diphosphate
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Guanylyl Imidodiphosphate
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Guanosine Triphosphate
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GTP Phosphohydrolases
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Proto-Oncogene Proteins p21(ras)
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Magnesium
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Lysine