posted on 2006-09-13, 00:00authored byClémence Allain, David Monchaud, Marie-Paule Teulade-Fichou
G-quadruplex represents a suitable scaffold for FRET (fluorescence resonance energy transfer)
since its two external quartets offer two well-defined binding sites for concomitant trapping of donor/acceptor
partners. Combining selective G-quadruplex binders (macrocyclic bis(quinacridine) BOQ1 or monomeric
quinacridine MMQ1, donor) with a highly fluorescent DNA probe (thiazole orange, acceptor), we designed
a structure-specific FRET-system based on an unprecedented noncovalent ternary complex. This system
could be potentially usable as a signature for quadruplex-DNA conformation in solution, but also might
offer a unique means for observing cation and ligand binding influence on quadruplex topology.