Genetically Encoded Fluorescent Probe for the Selective Detection of Peroxynitrite

Peroxynitrite is a highly reactive molecule involved in cell signaling and pathological processes. We hereby report a novel genetically encoded probe, pnGFP, which can selectively sense peroxynitrite. A boronic acid moiety was site-specifically introduced into circularly permuted fluorescent proteins. By examining different protein templates followed with site-targeted random mutagenesis, we identified a selective peroxynitrite sensor, which is essentially unresponsive to other common cellular redox signaling molecules. The new probe has been genetically introduced into mammalian cells to image peroxynitrite at physiologically relevant concentrations.