两性霉素B和其他多烯抗生素通过含甾醇膜囊泡诱导的渗透途径对Na +、K +和Cl -的选择性。
Na+, K+ and Cl- selectivity of the permeability pathways induced through sterol-containing membrane vesicles by amphotericin B and other polyene antibiotics.
作者信息
Hartsel S C, Benz S K, Ayenew W, Bolard J
机构信息
Chemistry Department, University of Wisconsin-Eau Claire 54701.
出版信息
Eur Biophys J. 1994;23(2):125-32. doi: 10.1007/BF00208866.
Membrane diffusion potentials induced by amphotericin B (AmB), amphotericin B methyl ester (AmE), N-fructosyl AmB (N FruAmB) and vacidin, an aromatic polyene antibiotic, in ergosterol- or cholesterol-containing egg yolk phosphatidylcholine large unilamellar vesicles (LUV), were measured in various media, in order to determine the relative selectivity of Na+, K+, Cl- and other ions in these environments. Changes in the membrane potential were followed by fluorescence changes of 3,3'-dipropylthiadicarbocyanine (diS-C3-(5)). Subtle changes in intercationic selectivity were monitored by measuring biionic potentials, using the fluorescent pH sensitive probe pyranine. In all the cases studied, the intercationic selectivity of the permeability pathways induced by the four antibiotics was weak compared to that of specific biological channels, though distinct differences were noted. With AmB the selectivity appeared to be concentration dependent. Above 5 x 10(-7) M, the sequence determined for sterol-free small unilamellar vesicles (SUV) and cholesterol-containing SUV and LUV, Na+ > K+ > Rb+ > or = Cs+ > Li+ (sulfate salts), corresponded closely to Eisenman selectivity sequence number VII. At 5 x 10(-7) M and below the selectivity switched from Na+ > K+ to K+ > Na+. In contrast, Li+ was the most permeant ion for AmB channels in the presence of ergosterol. The selectivity between Na+ or K+ vs. Cl- varied with the antibiotic. It was very strong with vacidin at concentrations below 5 x 10(-7) M, smaller with AmB, nil with AmE and N FruAmB. The selectivities observed were antibiotic, concentration and time dependent, which confirms the existence of different types of channels.
为了确定在这些环境中Na⁺、K⁺、Cl⁻和其他离子的相对选择性，在各种介质中测量了两性霉素B（AmB）、两性霉素B甲酯（AmE）、N-果糖基两性霉素B（N FruAmB）和一种芳香多烯抗生素瓦西丁在含麦角固醇或胆固醇的蛋黄磷脂酰胆碱大单层囊泡（LUV）中诱导的膜扩散电位。膜电位的变化通过3,3'-二丙基硫代二碳菁（diS-C3-(5)）的荧光变化来跟踪。使用荧光pH敏感探针吡喃荧光素通过测量双离子电位来监测阳离子间选择性的细微变化。在所研究的所有情况下，与特定生物通道相比，四种抗生素诱导的渗透途径的阳离子间选择性较弱，尽管注意到了明显差异。对于AmB，选择性似乎与浓度有关。在5×10⁻⁷ M以上，对于无甾醇小单层囊泡（SUV）以及含胆固醇的SUV和LUV确定的顺序，Na⁺＞K⁺＞Rb⁺＞或 = Cs⁺＞Li⁺（硫酸盐），与艾森曼选择性序列号VII密切对应。在5×10⁻⁷ M及以下，选择性从Na⁺＞K⁺转变为K⁺＞Na⁺。相比之下，在存在麦角固醇的情况下，Li⁺是AmB通道中渗透性最强的离子。Na⁺或K⁺与Cl⁻之间的选择性随抗生素而变化。在浓度低于5×10⁻⁷ M时，瓦西丁的选择性非常强，AmB的选择性较小，AmE和N FruAmB的选择性为零。观察到的选择性与抗生素、浓度和时间有关，这证实了不同类型通道的存在。
Zotero 插件