School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, Bremen 28759, Germany.
J Phys Condens Matter. 2010 Nov 17;22(45):454131. doi: 10.1088/0953-8984/22/45/454131. Epub 2010 Oct 29.
The permeation of water soluble molecules across cell membranes is controlled by channel-forming proteins and, in particular, the channel surface determines the selectivity. An adequate method to study the properties of these channels is electrophysiology and, in particular, analyzing the ion current fluctuation in the presence of permeating solutes. Ion current fluctuation analysis provides information on possible interactions of solutes with the channel surface. Due to the limited time resolution, fast permeation events are not visible using standard techniques. Here, we demonstrate that miniaturization of the lipid bilayer; varying the temperature or changing the solvent may enhance the resolution. Although electrophysiology is considered as a single molecule technique, it does not provide atomic resolution. Molecular details of solute permeation can be revealed by combining electrophysiology and all-atom computer modeling; these methods include ion conductance, selectivity, ion pair formation, and rate limiting interactions of the solute with the channel walls during permeation.
水溶性分子跨细胞膜的渗透由形成通道的蛋白质控制，特别是通道表面决定了选择性。研究这些通道特性的一种适当方法是电生理学，特别是分析存在渗透溶质时的离子电流波动。离子电流波动分析提供了溶质与通道表面可能相互作用的信息。由于时间分辨率有限，使用标准技术无法观察到快速渗透事件。在这里，我们证明脂质双层的小型化；改变温度或改变溶剂可以提高分辨率。尽管电生理学被认为是一种单分子技术，但它不能提供原子分辨率。通过将电生理学和全原子计算机建模相结合，可以揭示溶质渗透的分子细节；这些方法包括离子电导率、选择性、离子对形成以及溶质在渗透过程中与通道壁的限速相互作用。
