1aqg
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1aqg" size="450" color="white" frame="true" align="right" spinBox="true" caption="1aqg" /> '''NMR STRUCTURE OF THE RHODOPSIN-BOUND C-TERMI...)
Next diff →
Revision as of 08:55, 20 November 2007
|
NMR STRUCTURE OF THE RHODOPSIN-BOUND C-TERMINAL PEPTIDE OF THE TRANSDUCIN ALPHA-SUBUNIT, 20 STRUCTURES
Overview
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.
About this Structure
1AQG is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Tue Nov 20 11:02:52 2007
