THE MEMBRANE DIPOLE POTENTIAL IN A TOTAL MEMBRANE-POTENTIAL MODEL - APPLICATIONS TO HYDROPHOBIC ION INTERACTIONS WITH MEMBRANES
THE MEMBRANE DIPOLE POTENTIAL IN A TOTAL MEMBRANE-POTENTIAL MODEL - APPLICATIONS TO HYDROPHOBIC ION INTERACTIONS WITH MEMBRANES
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DOI：
10.1016/s0006-3495(86)83664-5
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发表时间：
1986-02-01
影响因子：
3.4
通讯作者：
HUBBELL, WL
中科院分区：
文献类型：
--
作者：
FLEWELLING, RF;HUBBELL, WL
疏水离子与脂质双层相互作用的总势能分布可以写成四个项的总和：电玻恩，图像和偶极贡献，和中性能量项。我们介绍了一个特定的模型的膜偶极子电位，把它作为一个二维阵列的点偶极子位于每个膜-水界面附近。连同其他能量项的具体理论模型，开发的总电位分布，成功地描述了两个疏水离子结构类似物，四苯基磷（TPP+）和四苯基硼（TPB-）的结合和易位的热力学参数的完整集合。如果偶极势能的大小为5.5 ± 0.5，则可能对数据进行合理的拟合。0.5 kcal/mol（240 ±. 20 mV），内部为正，并且如果TPP+和TPB-的中性能量贡献为-7.0. ±-。1.0千卡/摩尔这些结果也可能有重要的影响，小离子与膜的相互作用和膜蛋白中带电基团的能量学。
The total potential energy profile for hydrophobic ion interactions with lipid bilayers can be written as the sum of four terms: the electrical Born, image and dipole contributions, and a neutral energy term. We introduce a specific model for the membrane dipole potential, treating it as a two-dimensional array of point dipoles located near each membrane-water interface. Together with specific theoretical models for the other energy terms, a total potential profile is developed that successfully describes the complete set of thermodynamic parameters for binding and translocation for the two hydrophobic ion structural analogues, tetraphenylphosphonium (TPP+) and tetraphenylboron (TPB-). A reasonable fit to the data is possible if the dipole potential energy has a magnitude of 5.5 .+-. 0.5 kcal/mol (240 .+-. 20 mV), positive inside, and if the neutral energy contribution for TPP+ and TPB- is -7.0 .+-. 1.0 kcal/mol. These results may also have important implications for small ion interactions with membranes and the energetics of charged groups in membrane proteins.