Metarhodopsin-II stabilization by crosslinked Gtalpha C-terminal peptides and implications for the mechanism of GPCR-G protein coupling

Metarhodopsin-II is the light-excited form of rhodopsin that triggers G protein function. Metarhodopsin-II is stabilized when the N-terminus of the carboxyl (340-350) tail peptide of the alpha-subunit of transducin (Gtalpha) is crosslinked to rhodopsin cysteine 140 or the 340-350 peptide C-terminus...

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Bibliographic Details
Published in:Vision research (Oxford) 2006-12, Vol.46 (27), p.4547-4555
Main Authors: Angel, Thomas E, Kraft, Paul C, Dratz, Edward A
Format: Article
Language:English
Subjects:
Animals
Cattle
Cross-Linking Reagents
Cysteine - metabolism
Dark Adaptation
GTP-Binding Protein alpha Subunits - metabolism
Peptide Fragments - metabolism
Protein Binding
Receptors, G-Protein-Coupled - metabolism
Rhodopsin - chemistry
Rhodopsin - metabolism
Rod Cell Outer Segment - metabolism
Spectrum Analysis
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Summary:Metarhodopsin-II is the light-excited form of rhodopsin that triggers G protein function. Metarhodopsin-II is stabilized when the N-terminus of the carboxyl (340-350) tail peptide of the alpha-subunit of transducin (Gtalpha) is crosslinked to rhodopsin cysteine 140 or the 340-350 peptide C-terminus of Gtalpha is crosslinked to rhodopsin cysteine 316. When the N-terminus of the peptide is coupled to C316 the MIMII equilibrium is not affected. The evidence suggests that the N-terminus of the 340-350 region of Gtalpha is located near C140 when transducin stabilizes metarhodopsin-II and alternative explanations are suggested for the effectiveness of the 340-350 Gtalpha tail peptide when bound to C316.
ISSN:0042-6989