Fluorescence Lifetimes Of Dph Propionyl And Parinaroyl Ether And Ester Analogs Of Choline Glycerophospholipids In Unilamellar Vesicles

The fluorescence decay of sn-2 diphenylhexatrienylpropionyl- and parinaroyl-labeled choline glycerophospholipids as well as trimethylammonium-DPH (TMA-DPH) were determined by multifrequency phase fluorometry in single bilayer vesicles of diacylglycerophosphocholine (phosphatidylcholine) and its ether analog alkenylacylglycerophosphocholine (choline plasmalogen). The data were analyzed in terms of continuous lifetime distributions using Lorentzian distribution functions. Addition of cholesterol to the bilayers induced narrowing of the lifetime distributions for all labels and unlabeled matrix phospholipids tested. DPH propionyl phospholipids discriminated between ether (plasmalogen) and ester (phosphatidylcholine) phospholipid membranes in that they experienced a much larger lifetime heterogeneity when embedded in the ether lipid, even in the presence or absence of cholesterol.