Protein flexibility as revealed by fluorescence resonance energy transfer: an extension of the method for systems with multiple labels

Abstract

The temperature profile of the normalized fluorescence resonance energy transfer efficiency is capable of monitoring the relative change of flexibility and/or conformational state of macromolecules [Biochemistry 23 (1984) 3403]. The method described earlier for one donor–one acceptor systems is extended to multiple fluorophore systems when the energy transfer occurs between either one donor– m acceptors, or n donors–one acceptor or n donors– m acceptors (where n and m are integer values). It is shown that the normalized energy transfer efficiency obtained for systems containing multiple labels is a linear combination of the normalized transfer efficiency assigned to individual donor–acceptor pairs of the system, thus its temperature profile is capable of monitoring the change of intramolecular flexibility and/or conformational state.