A simplified approach to resonance energy transfer in membranes, lipoproteins and spatially restricted systems.

A general model is developed to simulate dipole-dipole resonance energy transfer in spatially restricted systems. At low concentrations of acceptor molecule, the overall quantum yield of a donor population can be defined quantitatively in terms of transfer to multiple defined acceptor regions. Energy transfer at higher acceptor concentrations can be approximated by assuming an exponential dependence of relative quantum yield on the acceptor concentrations. Through geometrical manipulations, this algorithm has been applied using an electronic calculator to systems in which donor-acceptor interaction is limited by unique steric restriction on donor and acceptor distribution within lipid aggregates. The systems that have been analyzed include monomolecular films, bilayer membranes, small discoidal lipid-protein complexes and plasma lipoproteins. The observed energy transfer from N-(2-naphthyl)-23,24-dinor-5-cholen-22-amide-3 beta-ol to N-dansyldimyristoylphosphatidylethanolamine in a dimyristoylphosphatidylcholine bilayer agrees with that predicted by this model.