title: The 2.2 A crystal structure of transducin-alpha complexed with GTP gamma S.
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.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510.
authors.forename: J P
authors.initials: JP
authors.lastname: Noel
authors.forename: H E
authors.initials: HE
authors.lastname: Hamm
authors.forename: P B
authors.initials: PB
authors.lastname: Sigler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002384:Catalysis; D002417:Cattle; D003196:Computer Graphics; D018360:Crystallography, X-Ray; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000737:chemistry* / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017948:Retinal Rod Photoreceptor Cells / Q000737:chemistry; D012243:Rhodopsin / Q000378:metabolism; D015293:Transducin / Q000737:chemistry* / Q000378:metabolism
chemical_list: D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D012243:Rhodopsin; D010727:Phosphoric Diester Hydrolases; D015293:Transducin