Sequential Multistep Energy Transfer: Enhancement of Efficiency of Long-Range Fluorescence Resonance Energy Transfer

We report a non-covalently linked chromophore array indicating sequential fluorescence resonance energy transfer (FRET) across three different chromophores. We have introduced different chromophores in a duplex of oligodeoxyribonucleic acid (oligo-DNA) in a sequential manner. We have revealed that the efficiency of FRET across the two chromophores at both ends of the oligo-DNA duplex is enhanced by a third chromophore located midway between them. The third chromophore works as a relay station in energy transfer.