Identification of alcohol-binding site(s) in proteins using diazirine-based photoaffinity labeling and mass spectrometry.

Defining molecular targets of alcohol and understanding the molecular mechanism of alcohol actions are necessary to develop effective therapeutics for alcohol use disorder (AUD). Here, we describe a detailed protocol for identifying alcohol-binding site(s) in proteins using diazirine-based azialcohol as photoaffinity labeling agents. Upon photoirradiation, azialcohol photoincorporates into alcohol-binding proteins. The stoichiometry and site of azialcohol photoincorporation can be determined using high-resolution mass spectrometry. Identification of the alcohol-binding residues in protein followed by measuring the biological significance of these residues in regulating alcohol action are important steps in characterizing the molecular targets of alcohol.