Cooperative partition model of nystatin interaction with phospholipid vesicles
Cooperative partition model of nystatin interaction with phospholipid vesicles
复制标题
DOI：
10.1016/s0006-3495(03)70032-0
复制
发表时间：
2003-05-01
影响因子：
3.4
通讯作者：
Prieto, M
中科院分区：
文献类型：
--
作者：
Coutinho, A;Prieto, M
制霉菌素是一种膜活性多烯抗生素，被认为通过形成离子渗透通道来杀死真菌细胞。在本报告中，我们通过时间分辨荧光测量研究了制霉菌素与不同尺寸（大和小单层囊泡）的磷酸胆碱脂质体的相互作用。我们的数据表明，抗生素与凝胶相 1,2-二棕榈酰-sn-甘油-3-磷酸胆碱囊泡相互作用的荧光发射衰减动力学受每个脂质体膜结合抗生素分子的平均数量控制（A）。抗生素从单体状态转变为寡聚状态，这与制霉菌素平均荧光寿命从大约 7-10 纳秒急剧增加到 35 纳秒有关，在每个脂质囊泡 10 个制霉菌素分子的临界浓度下开始发生。为了获得有关膜结合抗生素分子横向位置（渗透程度）的更多信息，在深度依赖性荧光猝灭实验中使用了自旋标记脂肪酸（5-和16-硬脂酸）。获得的结果表明单体制霉菌素锚定在磷脂/水界面上，并表明制霉菌素寡聚化伴随着其插入膜中。在全球范围内，实验数据通过协同分配模型定量描述，该模型假设单体制霉菌素分子分配到脂质双层表面并可逆地组装成 6 +/- 2 个抗生素分子的聚集体。
Nystatin is a membrane-active polyene antibiotic that is thought to kill fungal cells by forming ion-permeable channels. In this report we have investigated nystatin interaction with phosphaticlylcholine liposomes of different sizes (large and small unilamellar vesicles) by time-resolved fluorescence measurements. Our data show that the fluorescence emission decay kinetics of the antibiotic interacting with gel-phase 1,2-dipalmitoyl-sn-glycero-3-phosphocholine vesicles is controlled by the mean number of membrane-bound antibiotic molecules per liposome, (A). The transition from a monomeric to an oligomeric state of the antibiotic, which is associated with a sharp increase in nystatin mean fluorescence lifetime from similar to7-10 to 35 ns, begins to occur at a critical concentration of 10 nystatin molecules per lipid vesicle. To gain further information about the transverse location (degree of penetration) of the membrane-bound antibiotic molecules, the spin-labeled fatty acids (5- and 16-doxyl stearic acids) were used in depth-dependent fluorescence quenching experiments. The results obtained show that monomeric nystatin is anchored at the phospholipid/water interface and suggest that nystatin oligomerization is accompanied by its insertion into the membrane. Globally, the experimental data was quantitatively described by a cooperative partition model which assumes that monomeric nystatin molecules partition into the lipid bilayer surface and reversibly assemble into aggregates of 6 +/- 2 antibiotic molecules.