Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
J Chem Phys. 2018 Apr 7;148(13):135101. doi: 10.1063/1.5020754.
The electrostatic interactions play a crucial role in biological systems. Here we consider an impermeable dielectric molecule in the solvent with a different dielectric constant. The electrostatic free energy in the problem is studied in the Debye-Hückel regime using the analytical Green function that is calculated in the paper. Using this electrostatic free energy, we study the electrostatic contribution to the twist rigidity of a double stranded helical molecule such as a DNA and an actin filament. The dependence of the electrostatic twist rigidity of the molecule to the dielectric inhomogeneity, structural parameters, and the salt concentration is studied. It is shown that, depending on the parameters, the electrostatic twist rigidity could be positive or negative.
静电相互作用在生物系统中起着至关重要的作用。在这里，我们考虑在具有不同介电常数的溶剂中的不可渗透介电分子。使用本文中计算的解析格林函数，在德拜-休克尔区域研究了该问题中的静电自由能。利用这种静电自由能，我们研究了静电对双链螺旋分子（如 DNA 和肌动蛋白丝）的扭曲刚度的贡献。研究了分子的静电扭曲刚度对介电不均匀性、结构参数和盐浓度的依赖性。结果表明，取决于参数，静电扭曲刚度可能为正或负。
