IONIC DISTRIBUTION AROUND SIMPLE DNA MODELS .1. CYLINDRICALLY AVERAGED PROPERTIES
IONIC DISTRIBUTION AROUND SIMPLE DNA MODELS .1. CYLINDRICALLY AVERAGED PROPERTIES
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DOI：
10.1063/1.470191
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发表时间：
1995-11-08
影响因子：
4.4
通讯作者：
ABASCAL, JLF
中科院分区：
文献类型：
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作者：
MONTORO, JCG;ABASCAL, JLF
在添加（单价）盐浓度高达 2.5 M 的情况下，通过蒙特卡罗模拟计算几个简单 B-DNA 模型的属性取决于径向离子浓度分布。该模型包括均匀带电聚离子和离散带电聚离子。此外，还考虑了硬斥力和软斥力的影响。一个新颖的模型。介绍了以简化方式表示DNA沟槽结构的图。从方法论的角度来看，特别关注沿轴向方向的远程力的处理。使用离散带电聚电解质的精确公式。关于密度分布结果，得出的结论是，主要影响不是由于电荷位置的离散性，即均匀带电模型导致的特性与离散带电模型没有显着差异。类似的说法也适用于硬模型和软模型之间的比较。然而，DNA 凹槽形状的加入改变了这种行为。浓度分布函数中的双峰是由凹槽模型中排斥力和库仑力之间的耦合引起的。结果表明，我们的简化凹槽模型不仅可以充分预测 DNA 完整原子模型的这一特性，还可以充分预测其他特性。最后，在添加高浓度的盐时，可以看出凝聚的离子云过度中和了聚电解质电荷。这种电荷反转现象在所有研究的模型中都观察到，但由于需要高盐浓度，以前从未观察到过。 (C) 1995 年美国物理研究所。
Properties depending on the radial ionic concentration profiles are calculated by Monte Carlo simulation for several simple B-DNA models in the presence of added (monovalent) salt up to 2.5 M concentration. The models include both homogeneously and discretely charged polyions. Besides, the effect of hard and soft repulsive forces is considered. A novel model. which represents the DNA grooved structure in a simplified manner is introduced. From a methodological point of view, special attention is paid to the treatment of long-range forces along the axial direction. Exact formulas for discretely charged polyelectrolytes are used. Regarding the density profile results, it is concluded that the main effect is not due to the discreteness of the positions of the charges, i.e., homogeneously charged models lead to properties not significantly different from discretely charged ones. A similar statement holds for the comparison between hard and soft models. Nevertheless, the inclusion of the grooved shape of DNA modifies this behavior. A double hump in the concentration profile function is brought about by the coupling between repulsive and coulombic forces in the grooved model. It is shown that not only;this but also other properties of full atomic models of DNA are adequately predicted by our simplified grooved model. Finally, at high concentrations of added salt, it is seen that the condensed ionic cloud overneutralizes the polyelectrolyte charge. This charge reversal phenomenon, which is observed in all the models studied, has not been previously observed due to the high salt concentration required. (C) 1995 American Institute of Physics.