A genetically encodable and fluorogenic photo-crosslinker via photo-induced defluorination acyl fluoride exchange.

We report a genetically encodable m -trifluoromethylaniline modified L-lysine ( m -TFMAK) which defluorinates upon light activation and covalently conjugates to native residues via acyl fluoride exchange. The encoded m -TFMAK photo-crosslinks with temporal controllability, residue selectivity, and fluorogenic tracking features, making it suitable for identifying protein interactions in living systems.