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Updated: Jun 3, 2026

Genetically-encoded Molecular Probes to Study G Protein-coupled Receptors
Published on: September 13, 2013
Mapping the ligand-binding site on a G protein-coupled receptor (GPCR) using genetically encoded photocrosslinkers
Amy Grunbeck1, Thomas Huber, Pallavi Sachdev
1Laboratory of Molecular Biology and Biochemistry, The Rockefeller University, New York, New York, United States.
Abstract:
We developed a general cell-based photocrosslinking approach to investigate the binding interfaces necessary for the formation of G protein-coupled receptor (GPCR) signaling complexes. The two photoactivatable unnatural amino acids p-benzoyl-L-phenylalanine and p-azido-L-phenylalanine were incorporated by amber codon suppression technology into CXC chemokine receptor 4 (CXCR4). We then probed the ligand-binding site for the HIV-1 coreceptor blocker, T140, using a fluorescein-labeled T140 analogue. Among eight amino acid positions tested, we found a unique UV-light-dependent crosslink specifically between residue 189 and T140. These results are evaluated with molecular modeling using the crystal structure of CXCR4 bound to CVX15.
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