[3-(Trifluoromethyl)-3H-diazirin-3-yl]coumarin as a carbene-generating photocross-linker with masked fluorogenic beacon.

A coumarin-fused diazirine photolabeling agent exhibited dramatic enhancement in fluorescence after cross-linking with the target protein. Fluorescence emission from the coumarin moiety was efficiently quenched by the diazirine group, and was then intensively recovered from photolysis treatment by irradiation with light at a wavelength of 365 nm.