The effect of lipid A analog E5531 on membrane properties of dipalmitoylphosphatidylcholine

The effect of the lipid A analog E5531 on the phospholipid membrane was determined and compared with that of the lipid A from Escherichia coli (EC). E5531 decreased the phase transition temperature of dipalmitoylphosphatidylcholine (DPPC) membrane and increased the fluidity and permeability. On the other hand, EC increased the phase transition temperature and decreased the membrane fluidity and permeability. These results suggest that the reason for the difference of biological effects of E5531 and lipid A from EC would be caused by the differences from the effect on the cell membranes.