Interaction of polyene antibiotics with membrane lipids: physicochemical studies of the molecular basis of selectivity.
From various studies on the interaction of amphotericin B with unilamellar lipid vesicles, it appears that the strength of the binding does not depend only on the presence of sterol molecules in the membranes; and that several bound amphotericin B species are in competition, their relative amounts depending on the nature and percentage of sterol in the lipid bilayer. Bound amphotericin B molecules exchange rapidly between the membranes. It is therefore possible to add the antibiotic by transfer from amphotericin B-preloaded vesicles of dipalmitoylphosphatidylcholine, instead of direct addition. In these conditions the selectivity in the sensitivity to H+ leakage induced by amphotericin B between ergosterol- and cholesterol-containing vesicles is greatly enhanced. In the case of Mycoplasma laidlawii cells, a preliminary increase of K+ cellular content is observed when low doses of amphotericin B are added by transfer, an effect which is not observed with direct addition of the antibiotic.
D000666:Amphotericin B / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002784:Cholesterol; D002942:Circular Dichroism; D004875:Ergosterol; D008081:Liposomes / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism*; D011090:Polyenes / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D011663:Pulmonary Surfactants
D000900:Anti-Bacterial Agents; D008081:Liposomes; D008563:Membrane Lipids; D011090:Polyenes; D011663:Pulmonary Surfactants; D000666:Amphotericin B; D002784:Cholesterol; D011188:Potassium; D004875:Ergosterol