THERMODYNAMIC AND KINETIC-STUDIES ON THE ASSOCIATION OF MELITTIN WITH A PHOSPHOLIPID-BILAYER
THERMODYNAMIC AND KINETIC-STUDIES ON THE ASSOCIATION OF MELITTIN WITH A PHOSPHOLIPID-BILAYER
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DOI：
10.1016/0005-2736(89)90526-9
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发表时间：
1989-02-13
期刊：
影响因子：
--
通讯作者：
BESCHIASCHVILI, G
中科院分区：
文献类型：
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作者：
SCHWARZ, G;BESCHIASCHVILI, G
通过圆二色性、荧光能量转移和停流实验，研究了两亲肽蜂窝蜂素与二酰基磷脂酰胆碱单层囊泡的关系。圆二色性变化的肽与囊泡滴定（在低盐浓度）进行了分析，以产生热力学关联等温线。这些等温线被定量地解释为蜂毒素在水溶液和双层介质之间的单体-单体分配。这些数据可以很好地用基于gay - chapman表面势的理论曲线拟合。涉及化学修饰色氨酸的能量转移证实了相关肽缺乏聚集。根据动力学测量，这种结合在实际中是一个快速的一步过程，但不是完全扩散控制的。我们提出了一个简单的机制，其中固有的构象转变决定了总速率。
Association of the amphiphilic peptide melittin with unilamellar vesicles of dioleoylphosphatidylcholine has been experimentally investigated by means of circular dichroism, fluorescence energy transfer and stopped-flow experiments. Circular dichroism changes upon titration of the peptide with vesicles (at low salt concentration) were analyzed to yield thermodynamic association isotherms. These isotherms are quantitatively interpreted in terms of a monomer-monomer partitioning of melittin between the aqueous and bilayer media. The data can be very well fitted by theoretical curves based on a Gouy-Chapman surface potential. Energy transfer involving chemically modified tryptophan confirms a lack of aggregation of the associated peptide. According to the kinetic measurements the association proceeds in practice as a one-step process, which is rather fast but not fully diffusion-controlled. We proposed a simple mechanism where the inherent conformational transition determines the overall rate.