Biophysics and Molecular Biology: Tools and Techniques by Pearson

11

FRET and FRAP

11.1 FRET

FRET (Fluorescence Resonance Energy Transfer) is a phenomenon in which an excited donor molecule transfers energy (not an electron) to an acceptor molecule through a non-radiative process. It is a highly distance-dependent radiationless energy transfer process. In this energy transfer process, two molecules interact with each other in which one acts as donor and other as acceptor. The donor is a fluorophore that initially absorbs the energy and the acceptor is the fluorophore or chromophore to which the energy is subsequently transferred. A pair of molecules that interact in such a manner that FRET occurs is often referred to as a donor-acceptor pair.

Figure 11.1 A Jablonski diagram illustrating the coupled transitions ...