Spatiotemporally Controlled Photolabeling of Genetically Unmodified Proteins in Live Cells

Selective labeling of the protein of interest (POI) in genetically unmodified live cells is crucial for understanding protein functions and kinetics in their natural habitat. In particular, spatiotemporally controlled installation of the labels on a POI under light control without affecting their original activity is in high demand but is a tremendous challenge. Here, we describe a novel ligand-directed photoclick strategy for spatiotemporally controlled labeling of endogenous proteins in live cells. It was realized with a designer labeling reagent skillfully integrating the photochemistries of 2-nitrophenylpropyloxycarbonyl and 3-hydroxymethyl-2-naphthol with an affinity ligand. Highly electrophilic ortho-naphthoquinone methide was photochemically released and underwent a proximity coupling reaction with nucleophilic amino acid residues on the POI in live cells. With fluorescein as a marker, this photoclick strategy enables time-resolved labeling of carbonic anhydrase subtypes localized either on the cell membrane or in the cytoplasm and a discriminable visualization of their metabolic kinetics. Given the versatility underlined by facilely tethering other functional entities (e.g., biotin, a peptide short chain) via acylation or (in cell) Huisgen cycloaddition, this affinity-driven photoclick chemistry opens up enormous opportunities for discovering dynamic functions and mechanistic interrogation of endogenous proteins in live cells

Probable place of infection of cases of rhodesiense HAT diagnosed in non-DEC. 2011–2020.

The base layers used in this map are the FAO Global Administrative Unit Layers (GAUL) https://data.apps.fao.org/map/catalog/srv/eng/catalog.search#/metadata/9c35ba10-5649-41c8-bdfc-eb78e9e65654, Shuttle Radar Topography Mission (SRTM) https://www.usgs.gov/centers/eros/data-tools, FAO Inland water bodies in Africa https://data.apps.fao.org/map/catalog/srv/eng/catalog.search;jsessionid=B7AF7A215B16770A1A67C65D97FF21CA?node=srv#/metadata/bd8def30-88fd-11da-a88f-000d939bc5d8, and FAO Rivers of Africa https://data.apps.fao.org/map/catalog/srv/eng/catalog.search;jsessionid=B7AF7A215B16770A1A67C65D97FF21CA?node=srv#/metadata/b891ca64-4cd4-4efd-a7ca-b386e98d52e8.</p

Cases of HAT detected in non-DEC. 2000–2020.

Cases of HAT detected in non-DEC. 2000–2020.</p

Cases of HAT diagnosed in non-DEC. 2011–2020.

Circles represent the place of diagnosis; triangles indicate the probable place of infection. Gambiense HAT (red), rhodesiense HAT (blue). The base layers used in this map are the FAO Global Administrative Unit Layers (GAUL) https://data.apps.fao.org/map/catalog/srv/eng/catalog.search#/metadata/9c35ba10-5649-41c8-bdfc-eb78e9e65654 and FAO Inland water bodies in Africa https://data.apps.fao.org/map/catalog/srv/eng/catalog.search;jsessionid=B7AF7A215B16770A1A67C65D97FF21CA?node=srv#/metadata/bd8def30-88fd-11da-a88f-000d939bc5d8.</p

Institutions keeping prepositioned stocks of antitrypanosomal medicines for the treatment of HAT cases detected in non-DEC.

Institutions keeping prepositioned stocks of antitrypanosomal medicines for the treatment of HAT cases detected in non-DEC.</p

Cases of gambiense HAT diagnosed in non-DEC. 2011–2020.

Cases of gambiense HAT diagnosed in non-DEC. 2011–2020.</p