ABSTRACT
One of the most widely used methods for studying protein distributions and interactions in living cells is based on the detection of light from uorescent molecules. If a molecule (called “acceptor”) capable of absorbing light at wavelengths at which another one (called “donor”) emits, lies within a distance of less than 10 nm (or a hundred millionth of a meter) of the excited donor, the donor energy can be transferred to t he acceptor through a no n-radiative process called resonance energy transfer (RET) (Clegg 1996, Selvin 2000, Lakowicz 2006, Raicu and Popescu 2008). If the energy transfer occurs via long-range interaction between the transition dipoles of the donor and acceptor, the process is called Förster resonance energy transfer (FRET), a er eodore Förster, who was the rst to successfully model the RET using quantum mechanics calculations (Lakowicz 2006).
