Even though superresolution microscopy indicates that size of plasma membrane rafts is <20 nm, those structures have never been observed. Förster resonance energy transfer (FRET) is therefore still the most powerful optical method for characterization of such domains. In this letter we investigate relation between nanodomain affinity of a donor-acceptor (D/A) pair and the detectable nanodomain size/area. We show that probes with high affinity to the liquid-ordered (L(o)) phase are required for detecting domain sizes of a few nanometers, and/or domains that occupy a few percent of the bilayer area. A combination of donors and acceptors that prefer different phases is the more favorable approach. For instance, a D/A pair with the distribution constant of donors K(D) = 5 and acceptors K(A) = 0.01 can resolve a broad spectrum of nanodomain sizes. On the other hand, currently available donors and acceptors that prefer the same phase, either the liquid-disordered (L(d)) or L(o) phase, are not so convenient for determining domain sizes <20 nm. Here the detection limits of FRET experiments employing several commonly used D/A pairs have been investigated.

J Heyrovský Institute of Physical Chemistry v v i Academy of Sciences of the Czech Republic Prague Czech Republic

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Eggeling C., Ringemann C., Hell S.W. Direct observation of the nanoscale dynamics of membrane lipids in a living cell. Nature. 2009;457:1159–1162. PubMed

Hammond A.T., Heberle F.A., Feigenson G.W. Crosslinking a lipid raft component triggers liquid ordered-liquid disordered phase separation in model plasma membranes. Proc. Natl. Acad. Sci. USA. 2005;102:6320–6325. PubMed PMC

Heberle F.A., Wu J., Feigenson G.W. Comparison of three ternary lipid bilayer mixtures: FRET and ESR reveal nanodomains. Biophys. J. 2010;99:3309–3318. PubMed PMC

Chiantia S., Ries J., Schwille P. Combined AFM and two-focus SFCS study of raft-exhibiting model membranes. ChemPhysChem. 2006;7:2409–2418. PubMed

de Almeida R.F.M., Loura L.M.S., Prieto M. Lipid rafts have different sizes depending on membrane composition: a time-resolved fluorescence resonance energy transfer study. J. Mol. Biol. 2005;346:1109–1120. PubMed

Johansson L.B.A., Engstrom S., Lindberg M. Electronic energy transfer in anisotropic systems. 3. Monte Carlo simulations of energy migration in membranes. J. Chem. Phys. 1992;96:3844–3856.

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