3-Component lipid mixtures to model rafts: Finding phase boundaries and tie lines

COLL 85

Gerald W. Feigenson, Frederick Heberle, and David Stringer. Field of Biophysics, Cornell University, 201 Biotechnology Building, Ithaca, NY 14853
Determination of all of the phase boundaries in 3-component lipid bilayer mixtures is a difficult problem. Fluorescence resonance energy transfer (FRET) experiments, by use of probes having appropriate partition behavior between coexisting phases, can be sensitive to the phase separations. When phases coexist, FRET is enhanced if both donor and acceptor partition into the same phase. In this case, sensitivity is greatest near the phase boundary where there is only a small amount of the favored phase. A different FRET experiment makes use of donor and acceptor separating from each other when lipid phases coexist, yielding reduced FRET. We have achieved good definition of phase boundaries in sphingomyelin/DOPC/cholesterol bilayer mixtures and in DSPC/DOPC/cholesterol mixtures that contain four fluorescent dyes: two different donor/acceptor pairs, namely dehydroergosterol/perylene and 18:2,18:2-DiO/18:2,18:2-DiI.
 

Bio-Colloids
8:30 AM-11:30 AM, Monday, March 29, 2004 Marriott -- Grand Ballroom K, Oral

Division of Colloid and Surface Chemistry

The 227th ACS National Meeting, Anaheim, CA, March 28-April 1, 2004