Statistical Determinants of Selective Ionic Complexation: Ions in Solvent, Transport Proteins, and Other "Hosts"
Statistical Determinants of Selective Ionic Complexation: Ions in Solvent, Transport Proteins, and Other "Hosts"
复制标题
DOI：
10.1016/j.bpj.2009.03.001
复制
发表时间：
2009-06-03
影响因子：
3.4
通讯作者：
Brooks, Charles L., III
中科院分区：
文献类型：
--
作者：
Bostick, David L.;Brooks, Charles L., III
为了提供实用程序在理解离子选择性生物膜通道/转运蛋白，球状蛋白质和离子载体化合物的分子进化，以及在指导其修改和设计，我们提出了一个统计力学基础解构的影响的配位结构和化学选择性多齿离子复合物。解构增强了熟悉的想法在液体结构理论实现的离子络合物作为一个开放的离子连接系统的影响下，由主机（或周围介质）提供的“外场”。使用来自这个基础上的考虑，我们表明，选择性络合产生从开发一个特定的离子的协调偏好。这些偏好来自相互作用的平衡，就像决定霍夫迈斯特效应的平衡一样。通过分析的协调状态空间的小家庭IA和VIIA离子在模拟流体介质中，我们推导出域的协调状态，赋予一个给定的离子隔离和约束特定的属性（顺序参数）的复杂组成的给定类型的配体的选择性。我们证明，这样的域可以用来合理化的离子协调环境提供的选择性离子载体和生物离子通道/转运蛋白的已知结构，它们可以作为一种手段，对推导出合理的设计原则，离子选择性主机。
To provide utility in understanding the molecular evolution of ion-selective biomembrane channels/transporters, globular proteins, and ionophoric compounds, as well as in guiding their modification and design, we present a statistical mechanical basis for deconstructing the impact of the coordination structure and chemistry of selective multidentate ionic complexes. The deconstruction augments familiar ideas in liquid structure theory to realize the ionic complex as an open ion-ligated system acting under the influence of an "external field" provided by the host (or surrounding medium). Using considerations derived from this basis, we show that selective complexation arises from exploitation of a particular ion's coordination preferences. These preferences derive from a balance of interactions much like that which dictates the Hofmeister effect. By analyzing the coordination-state space of small family IA and VIIA ions in simulated fluid media, we derive domains of coordinated states that confer selectivity for a given ion upon isolating and constraining particular attributes (order parameters) of a complex comprised of a given type of ligand. We demonstrate that such domains may be used to rationalize the ion-coordinated environments provided by selective ionophores and biological ion channels/transporters of known structure, and that they can serve as a means toward deriving rational design principles for ion-selective hosts.