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Synthesis and Spectroscopic Characterization of Photo‐affinity Peptide Ligands to Study Rhodopsin–G Protein Interaction †
Author(s) -
Chen Yihui,
Herrmann Rolf,
Fishkin Nathan,
Henklein Peter,
Nakanishi Koji,
Ernst Oliver P.
Publication year - 2008
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2008.00304.x
Subject(s) - transducin , rhodopsin , heterotrimeric g protein , g protein coupled receptor , peptide , protein subunit , g protein , chemistry , receptor , biochemistry , stereochemistry , biology , retinal , gene
G protein‐coupled receptors (GPCRs) are involved in the control of virtually all aspects of our behavior and physiology. Activated receptors catalyze nucleotide exchange in heterotrimeric G proteins (composed of α·GDP, β and γ subunits) on the inner surface of the cell membrane. The GPCR rhodopsin and the G protein transducin (G t ) are key proteins in the early steps of the visual cascade. The main receptor interaction sites on G t are the C‐terminal tail of the G t α‐subunit and the farnesylated C‐terminal tail of the G t γ‐subunit. Synthetic peptides derived from these C‐termini specifically bind and stabilize the active rhodopsin conformation (R*). Here we report the synthesis of R*‐interacting peptides containing photo‐reactive groups with a specific isotope pattern, which can facilitate detection of cross‐linked products by mass spectrometry. In a preliminary set of experiments, we characterized such peptides derived from the farnesylated G t γ C‐terminus (G t γ(60‐71)far) in terms of their capability to bind R*. Here, we describe novel peptides with photo‐affinity labels that bind R* with affinities similar to that of the native G t γ(60‐71)far peptide. Such peptides will enable an improved experimental strategy to probe rhodopsin–G t interaction and to map so far unknown interaction sites between both proteins.