Ph_N3, Clickable APEX2 Probe

Ph_N3 is a cell-permeable, clickable phenol probe designed for high-efficiency APEX2-catalyzed RNA proximity labeling in live cells, where a brief H₂O₂ pulse generates a short-lived phenoxyl radical for irreversible covalent tagging of proximal biomolecules within a ~20 nm radius. This mechanism provides superior performance over biotin-phenol for spatially resolved RNA mapping (APEX-seq), demonstrated by the high-confidence enrichment of 15 mitochondrial transcripts in mito-APEX2 cells with minimal organelle perturbation. Ph_N3’s clickable azide handle offers dual bioorthogonal routes (CuAAC/SPAAC) for versatile downstream analysis. Critically, its mechanistic orthogonality to singlet oxygen (¹O₂)-mediated chemistry is a pivotal advantage, enabling unprecedented sequential dual-location labeling protocols to investigate biomolecular dynamics.