Effect of amphotericin B on cholesterol-containing liposomes of egg phosphatidylcholine and didocosenoyl phosphatidylcholine. A refinement of the model for the formation of pores by amphotericin B in membranes.
(1) Binding and K+-permeability measurements were performed on egg and 22 : 1c/22 : 1c-phosphatidylcholine liposomes with or without cholesterol. (2) Amphotericin B binds specifically to cholesterol in both types of liposome despite the difference in bilayer thickness. (3) Addition of amphotericin B to one side of the cholesterol-containing egg phosphatidylcholine bilayers induces a fast K+ efflux from the outermost compartment of the liposomes. In contrast, the total K+ content of sonicated unilamellar cholesterol-containing egg phosphatidylcholine vesicles is released by amphotericin B. (4) Amphotericin B addition to one side of the cholesterol-containing 22 : 1c/22 : 1c-phosphatidylcholine liposomes does not cause a change in K+ permeability. The presence of amphotericin B on both sides of the bilayer, however, induces an increase in K+ permeability. (5) A model is proposed which accounts for the effect of bilayer thickness on the amphotericin B-induced permeability changes in membranes.
D000666:Amphotericin B; D001665:Binding Sites; D002784:Cholesterol; D004531:Eggs; D005231:Fatty Acids, Unsaturated; D007473:Ion Channels; D008081:Liposomes; D008954:Models, Biological; D010539:Permeability; D010713:Phosphatidylcholines; D011188:Potassium
D005231:Fatty Acids, Unsaturated; D007473:Ion Channels; D008081:Liposomes; D010713:Phosphatidylcholines; D000666:Amphotericin B; D002784:Cholesterol; D011188:Potassium