Dr. Florence Kotzyba-Hibert, Dr. Isabelle Kapfer and Prof. Maurice Goeldner
Site-directed and efficient labeling of amino acids in biological receptors is possible with ligand analogues that form reactive intermediates on irradiation. This approach was used to label the binding sites of many receptors, for example by photoinduced coupling with (radioactive) nitrenes, carbocations, carbenes, and excited ketones [Eq. (a)]. The labeled amino acids are identified by proteolysis of the complex, purification, and sequencing. This method is well-suited for the study of ligand—receptor interactions and provides useful information for site-directed mutagenesis. □ = ligand, * = radioactive label, AA1, AA2, AA3 = amino acids.