Diazirine-PEG3-Biotin

Diazirine-PEG3-Biotin, a membrane-impermeable micromapping (µMAP) photo-proximity label, enables light-activated plasma membrane biotinylation. Diazirine′s spatiotemporal control and indiscriminate covalent insertion, via photoactivation (Dexter transfer), rapidly generate short-lived (<2 ns) triplet carbenes for controlled, high-resolution (2-120 nm radii, photocatalyst dependent) tagging of proximal membrane biomolecules. PEG3 linker enhances solubility and delivery, restricting diffusion for refined protein interaction mapping, crucial to map interactomes. Biotin (affinity handle) then enables efficient streptavidin/avidin enrichment and quantitative proteomics of the precisely labeled protein microenvironment.