Fig. 5
Proximity labeling by light and acylating reagents. A Chromophore-assisted proximity labeling (CAP)-Seq. A mini singlet oxygen generator (miniSOG) produces reactive oxygen species (ROS) upon blue-light illumination. ROS oxidize the guanine bases of nearby RNAs, which are then coupled to an alkyne amine and biotinylated via a click reaction. B Halo-Seq. Using the HaloTag system, an ROS generator, dibromofluorescein (DBF), is conjugated to a target protein. C Photoproximity protein interaction (PhotoPPI). The SNAP-tag system recruits a synthetic compound containing a diazirine, a biotin, and a UV-cleavable linker to a specific subcellular region. Upon UV irradiation, diazirine generates a reactive carbene that covalently labels proximal proteins. D Microenvironment mapping (µMap). Blue light exposure activates an iridium photocatalyst, which transfers energy to adjacent diazirines, generating singlet carbenes that label proximal biomolecules. E Bioorthogonal acylating agents for proximity labeling (BAP)-Seq. Acylating agents masked by a 1-methylcyclopropyl ester are activated by BS2 esterase localized in a specific subcellular region
