PHYSICS OF IONIC CHANNELS AND OTHER PROTEINS WITH AQUEOUS CAVITIES

离子通道和其他具有水腔的蛋白质的物理学

• 批准号: 5201625
• 负责人: V A PARSEGIAN
• 金额: --
• 依托单位: CENTER FOR INFORMATION TECHNOLOGY
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5201625
• 关键词: antibiotics; bioenergetics; biological signal transduction; biophysics; chemical kinetics; cytotoxicity; lipid bilayer membrane; macromolecule; membrane channels; membrane lipids; peptides; phospholipids; voltage gated channel; water solution

We have analyzed the signal transduction properties of voltage dependent ion channels in the presence of an external electric noise source. Experiments were done with planar lipid bilayers modified by alamethicin a well studied channel-forming peptide. A current response to a small sine-wave voltage signal was measured at different levels of admixed "white" noise. We showed that addition of external noise to this system input induces a significant increase of signal component at its output. This noise-induced enhancement in signal transductiion does not decrease the output signal-to-noise ratio and shows some features of the stochastic resonance. As we have previously shown by using phospholipid species with different tendency to form non-lamellar structures, alamethicin channels are sensitive to the inherent stress of lipid packing with a membrane. We are able to relate quantitatively the channel conformational equilibrium seen in its opening and closing statistics to the membrane packing energetics. This is done through the study of statistical characteristics of alamethicin channels incorporated into a charged lipid membrane. In these experiments the charge per lipid molecule is changed by varying the pH of the membrane-bathing solution.

我们分析了电压依赖的信号转导特性， 离子通道中存在的外部电噪声源。 实验用丙甲霉素修饰的平面脂质双层膜进行 一种被充分研究的通道形成肽。 一个小的电流响应 测量了不同掺量下的正弦波电压信号 “白色”噪音。 我们证明了在这个系统中加入外部噪声 输入在其输出处引起信号分量的显著增加。 这种噪声诱导的信号转导增强并不减少 输出信噪比，并显示了一些特点， 随机共振 正如我们先前通过使用具有不同磷脂种类所示， 倾向于形成非层状结构，丙甲霉素通道是 对具有膜的脂质包装的固有应力敏感。 我们 能够定量地关联通道构象平衡 在其开闭统计中看到， 能量学 这是通过统计学的研究完成的。 丙甲霉素通道与带电脂质结合的特性 膜的 在这些实验中，改变了每个脂质分子的电荷 通过改变膜浴溶液的pH值。