Studies on the structure of the G-protein-coupled receptor rhodopsin including the putative G-protein binding site in unactivated and activated forms.
Activation of G-protein coupled receptors (GPCR) is not yet understood. A recent structure showed most of rhodopsin in the ground (not activated) state of the GPCR, but the cytoplasmic face, which couples to the G protein in signal transduction, was not well-defined. We have determined an experimental three-dimensional structure for rhodopsin in the unactivated state, which shows good agreement with the crystal structure in the transmembrane domain. This new structure defines the cytoplasmic face of rhodopsin. The G-protein binding site can be mapped. The same experimental approach yields a preliminary structure of the cytoplasmic face in the activated (metarhodopsin II) receptor. Differences between the two structures suggest how the receptor is activated to couple with transducin.
Yeagle
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Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, USA. yeagle@uconnvm.uconn.edu
Choi
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Albert
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D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism*; D012243:Rhodopsin / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D011956:Receptors, Cell Surface; D012243:Rhodopsin; D019204:GTP-Binding Proteins