Jm. Muller et al., THE INTERPRETATION OF THE TIME-RESOLVED FLUORESCENCE ANISOTROPY OF DIPHENYILHEXATRIENE-PHOSPHATIDYLCHOLINE USING THE COMPOUND MOTION MODEL, Biochemical and biophysical research communications, 201(2), 1994, pp. 709-715
Time-resolved fluorescence anisotropy experiments on lipid membranes c
an provide estimates of the molecular order and motion on microscopic
scales. For the analysis of anisotropy data the socalled compound moti
on model. was recently introduced to overcome problems with convention
al models. We show that this novel model gives good fits for the time-
resolved anisotropy of the fluorescent probe diphenylhexatriene-phosph
atidylcholine (DPHPC) and can be succesfully used to interpret experim
ents with DPHPC embedded in small unilamellar vesicles of the lipids D
MPC, POPC, DOPC, DLPC, DERPC, DOPE, POPE, EGGPG and SQDG. The lifetime
and order parameters are found to be intermediate between those found
for the related DPH and TMA-DPH fluorescent probes, while the rotatio
nal diffusion of DPHPC is much slower. These findings can be rationali
sed in terms of the position of the DPH-fluorophore of DPHPC in the bi
layer. (C) 1994 Academic Press, Inc.