A “Quenchergenic” Chemoselective Protein Labeling Strategy

Abstract

Chemoselective labeling of a 5-hydroxytryptophan residue, which can be site-specifically incorporated into proteins through nonsense suppression, generates a highly chromophoric biarylazo group that is a potent fluorescence quencher. Its absorption behavior can be tuned by using distinct diazonium reagents to match the emission of different fluorescent probes.