Fluorescent Ribonucleoside as a FRET Acceptor for Tryptophan in Native Proteins

A new fluorescent ribonucleoside analogue, containing 5-aminoquinazoline-2,4(1H,3H)-dione, acts as a Forster resonance energy transfer acceptor for tryptophan (R-0 = 22 angstrom) and displays visible emission (440 nm). As tryptophan is frequently found at or near the recognition domains of RNA binding proteins, this FRET pair facilitates the study of RNA binding to native proteins and peptides, which is demonstrated here for the HIV-1 Rev association with the Rev Response Element (RRE).