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

Abstract

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.

Temperature‐induced structural change of integrin αvβ3 receptor and its interaction with the RGD peptide ligand

“…To improve the nano‐thermotherapy effect, it is necessary to study the ligand‐receptor interaction to gain information about the binding sites that still have binding affinity at high temperatures. [ 8–10 ]…”

“…To improve the nano-thermotherapy effect, it is necessary to study the ligand-receptor interaction to gain information about the binding sites that still have binding affinity at high temperatures. [8][9][10] Protein denaturation leads to changes in the binding site structure at high temperatures, and the changes in receptor protein structure with temperature need to be understood to improve the targeted delivery efficiency of NPs. [11][12][13][14] The expression of different proteins on the surface of Hela cells at high temperatures (39-45 C) was…”