1aqg

NMR STRUCTURE OF THE RHODOPSIN-BOUND C-TERMINAL PEPTIDE OF THE TRANSDUCIN ALPHA-SUBUNIT, 20 STRUCTURES

spinqualitylabelsall models 1aqg Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1aqg is a 1 chain structure with sequence from Bos taurus. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GNAT1_BOVIN Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. Transducin is an amplifier and one of the transducers of a visual impulse that performs the coupling between rhodopsin and cGMP-phosphodiesterase. Publication Abstract from PubMed A large superfamily of transmembrane receptors control cellular responses to diverse extracellular signals by catalyzing activation of specific types of heterotrimeric GTP-binding proteins. How these receptors recognize and promote nucleotide exchange on G protein alpha subunits to initiate signal amplification is unknown. The three-dimensional structure of the transducin (Gt) alpha subunit C-terminal undecapeptide Gtalpha(340-350) IKENLKDCGLF was determined by transferred nuclear Overhauser effect spectroscopy while it was bound to photoexcited rhodopsin. Light activation of rhodopsin causes a dramatic shift from a disordered conformation of Gtalpha(340-350) to a binding motif with a helical turn followed by an open reverse turn centered at Gly-348, a helix-terminating C capping motif of an alphaL type. Docking of the NMR structure to the GDP-bound x-ray structure of Gt reveals that photoexcited rhodopsin promotes the formation of a continuous helix over residues 325-346 terminated by the C-terminal helical cap with a unique cluster of crucial hydrophobic side chains. A molecular mechanism by which activated receptors can control G proteins through reversible conformational changes at the receptor-G protein interface is demonstrated. Light-activated rhodopsin induces structural binding motif in G protein alpha subunit.,Kisselev OG, Kao J, Ponder JW, Fann YC, Gautam N, Marshall GR Proc Natl Acad Sci U S A. 1998 Apr 14;95(8):4270-5. PMID:9539726 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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