Light-Controlled Traceless Protein Labeling via Decaging Thio-o-naphthoquinone Methide Chemistry

Abstract

We report the molecular design of a novel multifunctional reagent and its application for light-controlled selective protein labeling. This molecule integrates functions of protein–ligand recognition, bioconjugation, ligand cleavage, and photoactivation by merging the photochemistries of 2-nitrophenylpropyloxycarbonyl and 3-hydroxymethyl-2-naphthol with an affinity ligand and fluorescein. Highly electrophilic o-naphthoquinone methide was photochemically released and underwent proximity-driven selective labeling with the protein of interest (e.g., carbonic anhydrases), which retains its native function after labeling.

Spatiotemporally Controlled Photolabeling of Genetically Unmodified Proteins in Live Cells

“…A decaging thio-o-naphthoquinone methide chemistry (DTNM chemistry) designed in our previous work was a light-controlled spatiotemporal protein labeling strategy that targets a genetically unmodified POI in live cells without affecting its native activity. 38 Decaging thio-o-naphthoquinone methide chemistry is composed with a tailored photoclick molecule connecting the recognition ligand and the labeling probe, which concurrently takes into account the following concerns: (1) A reactive electrophile is photochemically generated in situ that can rapidly conjugate to reactive amino acids near the ligand-binding site of the POI. (2) The recognition moiety that disconnects from the probe could leave the recognition pocket due to reversible binding to ensure protein activity for further functional study of the labeled POI in live cells.…”