Abstract
The 2.2 A crystal structure of activated rod transducin, Gt alpha.GTP gamma S, shows the bound GTP gamma S molecule occluded deep in a cleft between a domain structurally homologous to small GTPases and a helical domain unique to heterotrimeric G proteins. The structure, when combined with biochemical and genetic studies, suggests: how an activated receptor might open this cleft to allow nucleotide exchange; a mechanism for GTP-induced changes in effector and receptor binding surfaces; and a mechanism for GTPase activity not evident from previous data.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Catalysis
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Cattle
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Computer Graphics
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Crystallography, X-Ray
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Guanosine 5'-O-(3-Thiotriphosphate) / chemistry*
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Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
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Guanosine Diphosphate / metabolism
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Guanosine Triphosphate / metabolism
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Hydrolysis
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Models, Molecular
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Molecular Sequence Data
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Phosphoric Diester Hydrolases / metabolism
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Protein Binding
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Protein Conformation
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Retinal Rod Photoreceptor Cells / chemistry
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Rhodopsin / metabolism
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Transducin / chemistry*
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Transducin / metabolism
Substances
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Guanosine Diphosphate
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Guanosine 5'-O-(3-Thiotriphosphate)
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Guanosine Triphosphate
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Rhodopsin
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Phosphoric Diester Hydrolases
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Transducin