Fluorescence Resonance Energy Transfer in the Studies of Guanine Quadruplexes

A guanine (G)-quadruplex DNA motif has recently emerged as a biologically important structure that is believed to interfere with telomere maintenance by telomerase.G-quadruplexes exhibit four-stranded structures containing one or more nucleic acid strands with central channel able to accommodate metal cations.Coordination of certain metal cations stabilizes G-quadruplex as with some promising small organic molecules that promote the formation and/or stabilization of G-quadruplex.Among many techniques employed to explore properties of G-quadruplexes,the fluorescence resonance energy transfer (FRET)technique has been recognized as a powerful tool to study G-quadruplex formation.This review summarizes the current developments in the uses of FRET technique for the fundamental structural investigations and its practical applications.Applications include FRET-based selection of efficient quadruplex-binding ligands,design of a nanomolecular machine,and a molecular aptamer beacon for protein recognition.We also describe a technique for detection of potassium ions in aqueous solution with the use of quadruplex-based sensor (potassium-sensing oligonucleotide).