Effects of pH and temperature on photoaffinity labeling of Family B G protein-coupled receptors

Maoqing Dong, Laurence J. Miller

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4 Citations (Scopus)


The efficiency of covalent labeling of a receptor by a photolabile analogue of its natural ligand is dependent on the spatial approximation of the probe and its target. Systematic application of intrinsic photoaffinity labeling to the secretin receptor, a prototypic Family B G protein-coupled receptor, demonstrated reduced efficiency of labeling for amino-terminal and mid-region sites of labeling relative to carboxyl-terminal sites. Reduction of pH from 7.4 to 5.5 and reduction of temperature from 25 °C to 4 °C improved the efficiency of covalent labeling of the receptor with these probes. This correlated with sites of labeling at the interface between the receptor amino terminus and the receptor core, a region containing histidine residues that have their ionization affected in this pH range. Application to the calcitonin receptor, another Family B G protein-coupled receptor, yielded analogous results. These results support the consistent mode of docking peptide ligands to this group of receptors.

Original languageEnglish
Pages (from-to)110-115
Number of pages6
JournalRegulatory Peptides
Issue number1-3
Publication statusPublished - 27 Nov 2009
Externally publishedYes


  • Calcitonin receptor
  • G protein-coupled receptors
  • Photoaffinity labeling
  • Secretin receptor

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