Analytical Modeling of the Ion Number Fluctuations in Biological Ion Channels
Analytical Modeling of the Ion Number Fluctuations in Biological Ion Channels
复制标题
生物离子通道中离子数波动的分析模型
DOI：
10.1166/jnn.2012.5771
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发表时间：
2012
影响因子：
--
通讯作者：
Pandey, Santosh
中科院分区：
文献类型：
--
作者：
Pandey, Santosh
离子通道是跨膜蛋白，其调节和维持跨细胞膜的离子浓度。模拟通过这些通道的原子级离子通量对于理解几种神经疾病和相关药物发现至关重要。实验技术现在提供的信息渠道的物理结构，这有助于发展realisticion传输模型。进入通道的离子在穿过通道时遵循不同的轨迹;每个轨迹与一定的概率相关联。解释这些轨迹的参数是离子数波动的移位和返回概率、平均寿命和谱密度（一个实验可获得的参数）。离子输运的理论分析一直局限于低分辨率的连续扩散为基础的或动力学为基础的模型。这种分析模型未能包括影响离子传导的关键因素。在本文中，我们扩展了以前的模型的电扩散模型，将电场的影响，能量势垒，和速率限制的关联/解离的离子与通道内的表面电荷。生存概率和谱密度来自分析模型。
Ion channels are transmembrane proteins that regulate and maintain the ionic concentrations across the cell membrane. Modeling the atomistic-level ionic flux through these channels is crucial for the understandingof several neurological diseases and related pharmaceutical discoveries. Experimental techniques now provide information about the channel's physical structure which helps in developing realisticion transport models. Ions entering a channel follow different trajectories as they traverse the channel; each associated with a certain probability. Quantities that explain these trajectories are the translocation and return probabilities, average lifetime, and spectral density (an experimentally accessible parameter) of ion number fluctuations. Theoretical analysis of ion transport has been limited to low-resolution continuum diffusion-based or kinetic-based models. Such analytical models fail to include key factors affecting the ionic conduction. In this paper, we extend previous models by an electro-diffusion model incorporating the effects of electric field, energy barrier, and rate-limited association/dissociation of ions with surface charges inside the channel. Survival probability and spectral density are derived from the analytical model.