The influence of amphotericin B on the molecular organization and structural properties of DPPC lipid membranes modified by sterols

In this work, we studied the influence of the polyene antibiotic amphotericin B (AmB) on dipalmitoylphosphatidylcholine (DPPC) multibilayers modified by cholesterol and ergosterol investigated by means of X-ray diffraction. The periodic structures related to AmB–DPPC–sterol complexes in multibilayers are completely created in temperatures above the main lipid phase transition. The differences between all observed multilayer structures are related to the thickness. Multibilayers composed of lipid and sterols have similar thickness of 51 Å. Addition of amphotericin B leads to creation of new periodic structures. Multibilayers composed of lipid–ergosterol–AmB have thickness of 44 Å which does not change with temperature. Multibilayers composed of lipid–cholesterol–AmB at 20 °C are 43 Å and gets thicker at 50 °C. Most probably this is caused by weaker van der Vaals cholesterol–amphotericin B interactions.