Communication: Charge, diffusion, and mobility of proteins through nanopores
Communication: Charge, diffusion, and mobility of proteins through nanopores
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DOI：
10.1063/1.4894401
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发表时间：
2014-08-28
影响因子：
4.4
通讯作者：
Muthukumar, M.
中科院分区：
文献类型：
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作者：
Muthukumar, M.
将电荷、扩散系数和迁移率联系起来的爱因斯坦定律的实施面临着严重的困难，以解释通过纳米孔从单分子电泳法获得的蛋白质实验数据。根据爱因斯坦定律推断的蛋白质电荷和扩散系数可以比它们的裸值小几个数量级，这取决于电解液浓度、孔径、孔壁的化学性质和外部施加的电压。造成差异的主要因素是蛋白质及其反离子云的耦合动力学、孔内的限制效应以及蛋白质-孔-表面的相互作用。我们通过听取经典的大离子电泳学和毛孔内流体动力学的理论来解决这些成分，并得出了关于毛孔-蛋白质相互作用的新结果。在单分子电泳法实验中，我们结合不同的成分，给出了蛋白质的有效电荷、扩散系数和迁移率的近似解析公式。对于无处不在的孔道-蛋白质相互作用，给出了电压组对蛋白质速度的非线性依赖关系，并给出了该效应的解析公式。推导出的公式可以根据实验测量的表观值确定蛋白质的裸电荷和大小。(C)2014 AIP出版有限责任公司。
Implementation of Einstein's law connecting charge, diffusion coefficient, and mobility to interpret experimental data on proteins from single molecule electrophoresis through nanopores faces serious difficulties. The protein charge and diffusion coefficient, inferred with the Einstein law, can be orders of magnitude smaller than their bare values depending on the electrolyte concentration, pore diameter, chemical nature of the pore wall, and the externally applied voltage. The main contributors to the discrepancies are the coupled dynamics of the protein and its counterion cloud, confinement effects inside the pore, and the protein-pore-surface interaction. We have addressed these ingredients by harking on classical theories of electrophoresis of macroions and hydrodynamics inside pores, and deriving new results for pore-protein interactions. Putting together various components, we present approximate analytical formulas for the effective charge, diffusion coefficient, and mobility of a protein in the context of single molecule electrophoresis experiments. For the omnipresent pore-protein interactions, nonlinear dependence of the velocity of protein on voltage sets in readily and analytical formulas for this effect are presented. The derived formulas enable the determination of the bare charge and size of a protein from the experimentally measured apparent values. (C) 2014 AIP Publishing LLC.