Circular dichroism study of the interaction between aromatic heptaene antibiotics and small unilamellar vesicles.

Unlike the non-aromatic heptaene amphotericin B, only two types of complex are revealed by circular dichroism when the aromatic heptaenes interact with lipid vesicles. The first is formed when no permeability is observed. The second one is correlated with the appearance of permeability. The cholesterol concentration and the physical state of the membrane have influence only on the amount of the permeabilizing species. These results indicate important differences in the membrane properties of aromatic and non-aromatic heptaenes.