论文标题
外部电场中DNA双螺旋在DNA双螺旋周围的K $^+$柜台的动力学：一项分子动力学研究
Dynamics of K$^+$ counterions around DNA double helix in the external electric field: a molecular dynamics study
论文作者
论文摘要
DNA双螺旋的结构被金属柜台稳定在大分子周围的弥漫层。在实际条件下，柜台的动力学受DNA和其他生物学大分子的电场控制。在目前的工作中，分子动力学研究{}对DNA双螺旋的系统进行了中和具有中和的K $^+$柜台，以及在不同强度的外部电场中的KCL盐溶液系统（最高32 mV/Å）。对这些系统的离子电导率的分析{表明}表明，与KCL盐溶液相比，DNA双螺旋周围的反构件会减慢。计算出的{离子迁移率值}在（0.05 $ $ 0.4）MS/cm之内，具体取决于外部电场相对于双螺旋的方向。在与大分子k $^+$柜台平行的电场下，双螺旋的凹槽移动在较窄的小凹槽的位置更长。在垂直于大分子的电场下，柜台的动力学受DNA原子的影响较小，从约30 mV/Å的电场值开始，双螺旋从双链到单链状态进行相变。
The structure of DNA double helix is stabilized by metal counterions condensed to a diffuse layer around the macromolecule. The dynamics of counterions in real conditions is governed by the electric fields from DNA and other biological macromolecules. In the present work the molecular dynamics study {was} performed for the system of DNA double helix with neutralizing K$^+$ counterions and for the system of KCl salt solution in the external electric field of different strength (up to 32 mV/Å). The analysis of ionic conductivities of these systems {has shown} that the counterions around the DNA double helix are slowed down compared with KCl salt solution. The calculated {values of ion mobility} are within (0.05$÷$0.4) mS/cm depending on the orientation of the external electric field relatively to the double helix. Under the electric field parallel to the macromolecule K$^+$ counterions move along the grooves of the double helix staying longer in the places with narrower minor groove. Under the electric field perpendicular to the macromolecule the dynamics of counterions is less affected by DNA atoms, and starting with the electric field values about 30 mV/Å the double helix undergoes a phase transition from double-stranded to single-strand state.
