1AQG

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

Summary for 1AQG

• Entry DOI: 10.2210/pdb1aqg/pdb
• Descriptor: TRANSDUCIN ALPHA-1 SUBUNIT (1 entity in total)
• Functional Keywords: transducer, transducin, rhodopsin, gtp-binding
• Biological source: Bos taurus (cattle)
• Total number of polymer chains: 1
• Total formula weight: 1281.52

Authors

Kisselev, O.G.,Marshall, G.R. (deposition date: 1997-07-29, release date: 1998-07-29, Last modification date: 2024-05-22)

Primary citation

Kisselev, O.G.,Kao, J.,Ponder, J.W.,Fann, Y.C.,Gautam, N.,Marshall, G.R.
Light-activated rhodopsin induces structural binding motif in G protein alpha subunit.
Proc.Natl.Acad.Sci.USA, 95:4270-4275, 1998

PubMed Abstract: 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.

PubMed: 9539726
DOI: 10.1073/pnas.95.8.4270

Experimental method

SOLUTION NMR