Quantitation of the Förster energy transfer for two-dimensional systems. II. Protein distribution and aggregation state in biological membranes.

Analytical solutions are presented of the average rate of the Förster energy transfer for several processes affecting intrinsic membrane proteins within a phospholipid bilayer. The physiol phenomena considered here are: lateral phase separation of the protein, i.e., formation of eutectic mixtures, changes in the aggregation state of the protein and non-random distribution of protein molecules. It is shown that the average rate of energy transfer among protein and phospholipid molecules labelled with donor and acceptor molecules, respectively, allows differentiation between them and also that the average rate of energy transfer can be used to quantitate these phenomena.