Photoaffinity Labeling of the Human A_2A Adenosine Receptor and Cross-link Position Analysis by Mass Spectrometry

Photoaffinity labeling (PAL) is widely used for the identification of ligand-binding proteins and elucidation of ligand-binding sites. PAL has also been employed for the characterization of G protein-coupled receptors (GPCRs); however, a limited number of reports has successfully identified their cross-linked amino acids. This report is the first of its kind to determine the cross-link position of the human A_2A adenosine receptor by PAL with the novel diazirine-based photoaffinity probe 9.