Grigorjev P, Schlegel R, Thrum H, Ermishkin L
Biochim Biophys Acta. 1985 Dec 5;821(2):297-304. doi: 10.1016/0005-2736(85)90099-9.
Ion permeability of lipid bilayers was studied in the presence of a new antifungal pentaene antibiotic, roflamycoin, the structure of which differs considerably from that of the well-known polyene channel-former amphotericin B. Both of them, however, show the property of increasing the membrane permeability only in the case of sterol-containing membrane when added on both its sides. The conductance is strongly dependent on the concentration of the antibiotic in the solutions and of sterol in the membrane. Unlike the amphotericin B channels, roflamycoin channels are potential-dependent and have short lifetime (approx. 1 s) and high conductance (approx. 100 ps in 1 M KCl), which increases linearly with the salt concentration and is not blocked by the familiar blockers of amphotericin B channels. The two antibiotics seem to have a common mechanism of channel formation, viz. the formation starts from two semi-pores assembled in the opposite monolayers from several molecules of the antibiotic and sterol. However, the inner diameter of the roflamycoin channel is larger because of the different antibiotic-to-sterol ratio in the channel aggregate. It is believed that the difference in the ratio is due to the presence of the methyl group in the polyene chain of roflamycoin, and the considerable difference in lifetimes of the two types of channels depends on the terminal groups of the antibiotics.
在一种新型抗真菌戊二烯抗生素罗弗米星存在的情况下，研究了脂质双层的离子通透性。罗弗米星的结构与著名的多烯通道形成剂两性霉素B有很大不同。然而，当将它们添加到含甾醇膜的两侧时，二者都表现出仅在含甾醇膜的情况下增加膜通透性的特性。电导率强烈依赖于溶液中抗生素的浓度以及膜中甾醇的浓度。与两性霉素B通道不同，罗弗米星通道是电位依赖性的，寿命短（约1秒）且电导率高（在1M KCl中约为100 pS），电导率随盐浓度线性增加，并且不受两性霉素B通道常见阻滞剂的阻断。这两种抗生素似乎具有共同的通道形成机制，即通道形成始于由几个抗生素和甾醇分子在相对的单层中组装而成的两个半孔。然而，由于通道聚集体中抗生素与甾醇的比例不同，罗弗米星通道的内径更大。据信，比例差异是由于罗弗米星多烯链中存在甲基，并且两种通道寿命的显著差异取决于抗生素的末端基团。
