Ollivon M, Eidelman O, Blumenthal R, Walter A
Section on Membrane Structure and Function, LTB, National Cancer Institute, Bethesda, Maryland 20892.
Biochemistry. 1988 Mar 8;27(5):1695-703. doi: 10.1021/bi00405a047.
The dissolution and formation of egg phosphatidylcholine (PC) vesicles by the detergent octyl glucoside were examined systematically by using resonance energy transfer between fluorescent lipid probes, turbidity, and gel filtration chromatography. Resonance energy transfer was exquisitely sensitive to the intermolecular distance when the lipids were in the lamellar phase and to the transitions leading to mixed micelles. Turbidity measurements provided information about the aggregation of lipid and detergent. Several reversible discrete transitions between states of the PC-octyl glucoside system were observed by both methods during dissolution and vesicle formation. These states could be described as a series of equilibrium structures that took the forms of vesicles, open lamellar sheets, and mixed micelles. As detergent was added to an aqueous suspension of vesicles, the octyl glucoside partitioned into the vesicles with a partition coefficient of 63. This was accompanied by leakage of small molecules and vesicle swelling until the mole fraction of detergent in the vesicles was just under 50% (detergent:lipid ratio of 1:1). Near this point, a transition was observed by an increase in turbidity and release of large molecules like inulin, consistent with the opening of vesicles. Both a turbidity maximum and a sharp increase in fluorescence were observed at a detergent to lipid mole ratio of 2.1:1. This was interpreted as the lower boundary of a region where both lamellar sheets and micelles are at equilibrium. At a detergent:lipid ratio of 3.0:1, another sharp change in resonance energy transfer and clarification of the suspension were observed, demarcating the upper boundary of this two-phase region. This latter transition is commonly referred to as solubilization.(ABSTRACT TRUNCATED AT 250 WORDS)
通过使用荧光脂质探针之间的共振能量转移、浊度和凝胶过滤色谱法，系统地研究了去污剂辛基葡糖苷对鸡蛋磷脂酰胆碱（PC）囊泡的溶解和形成过程。当脂质处于片层相时，共振能量转移对分子间距离以及导致混合胶束的转变极为敏感。浊度测量提供了有关脂质和去污剂聚集的信息。在溶解和囊泡形成过程中，两种方法均观察到PC - 辛基葡糖苷系统状态之间的几个可逆离散转变。这些状态可以描述为一系列平衡结构，其形式为囊泡、开放片层和混合胶束。当向囊泡的水悬浮液中加入去污剂时，辛基葡糖苷以63的分配系数分配到囊泡中。这伴随着小分子的泄漏和囊泡肿胀，直到囊泡中去污剂的摩尔分数刚好低于50%（去污剂：脂质比为1:1）。接近这一点时，观察到浊度增加和菊粉等大分子释放的转变，这与囊泡的开放一致。在去污剂与脂质摩尔比为2.1:1时，观察到浊度最大值和荧光急剧增加。这被解释为片层和胶束处于平衡的区域的下边界。在去污剂：脂质比为3.0:1时，观察到共振能量转移的另一个急剧变化和悬浮液的澄清，划定了这个两相区域的上边界。后一种转变通常称为增溶作用。（摘要截断于250字）
