A Protein Fluorescence Amplifier: Continuous Fluorometric Assay for Rab Geranylgeranyltransferase

A 23-fold enhancement of fluorescence is observed upon RabGGTase-mediated protein prenylation by NBD-FPP. We propose that the chaperone of prenylated Rab GTPases, REP, which harbors the conjugated prenyl moieties, functions as a fluorescence amplifier and leads to intermolecular fluorescence enhancement. This reaction was characterized and used to develop a fluorescent prenylation assay that can be adapted for a high-throughput format.