Extended dipolar chain model for ion channels: electrostriction effects and the translocational energy barrier.
Extended dipolar chain model for ion channels: electrostriction effects and the translocational energy barrier.
复制标题
DOI：
10.1016/s0006-3495(95)80204-3
复制
发表时间：
1995-02
影响因子：
3.4
通讯作者：
M. Sancho;M. Partenskii;V. Dorman;Peter C. Jordan
中科院分区：
文献类型：
--
作者：
M. Sancho;M. Partenskii;V. Dorman;Peter C. Jordan
我们重新研究离子通道的偶极链模型。我们的目标是占离子诱导的电致伸缩的通道水的影响，在通道中的不同离子所经历的易位能垒。为了这个目的，我们完善我们的前模型放松的离子和水偶极子的位置约束，并通过包括Lennard-Jones的贡献，除了静电相互作用。离子和沃茨的位置通过自由能的最小化来确定。如前所述，与外部介质的相互作用通过图像力来描述。碱金属阳离子的应用表明，短程相互作用调制的自由能分布导致的选择性序列易位。我们研究了一些结构参数对该序列的影响，并将我们的理论预测与短杆菌肽的观测结果进行了比较。
We reinvestigate the dipolar chain model for an ion channel. Our goal is to account for the influence that ion-induced electrostriction of channel water has on the translocational energy barriers experienced by different ions in the channel. For this purpose, we refine our former model by relaxing the positional constraint on the ion and the water dipoles and by including Lennard-Jones contributions in addition to the electrostatic interactions. The positions of the ion and the waters are established by minimization of the free energy. As before, interaction with the external medium is described via the image forces. Application to alkali cations show that the short range interactions modulate the free energy profiles leading to a selectivity sequence for translocation. We study the influence of some structural parameters on this sequence and compare our theoretical predictions with observed results for gramicidin.