论文标题
DNA双螺旋周围的柜台大气：纳米级的反面捕获
Counterion atmosphere around DNA double helix: trapping of counterions at the nanoscale
论文作者
论文摘要
DNA是强大的聚电解质大分子，使金属离子（柜台）凝结在双螺旋周围的云层上。柜台可能位于大分子外部以及双螺旋螺旋的小型和主要凹槽内。在目前的工作中，已经使用反式凝结理论的方法研究了DNA内部和外部区域之间的凝结柜台的分布。结果表明，被困在大分子内部的抗衡值应大于每一个磷酸盐组0.16。 DNA双螺旋内可能位于DNA双螺旋内的最大反面数限制为每一个磷酸盐组约0.4，并且远低于凝结柜台的总数。为了分析反云的结构，已经执行了\ emph {b} -DNA的分子动力学模拟，其中具有K $^{+} $柜台。与模型估计相一致的每一个磷酸盐基团的凹槽内部的计数器数量约为0.22 $ \ pm $ 0.06。开发的模型描述了DNA围绕DNA周围的反动云结构的一般特征，并能够预测双螺旋凹槽内部的反面数量。
DNA is strong polyelectrolyte macromolecule making metal ions (counterions) condense to a cloud around the double helix. The counterions may be localized outside the macromolecule and inside the minor and major grooves of the double helix. In the present work, the distribution of condensed counterions between inner and outer regions of DNA has been studied using the approaches of counterion condensation theory. The results have shown that the number of counterions trapped inside the macromolecule should be greater than 0.16 per one phosphate group. The maximal number of counterions that may be localized inside the DNA double helix is limited to about 0.4 per one phosphate group and it is much lower than the total number of condensed counterions. To analyze the structure of counterion cloud the molecular dynamics simulations of \emph{B}-DNA with K$^{+}$ counterions have been performed. The obtained number of the counterions trapped inside the grooves of the double helix is about 0.22$\pm$0.06 per one phosphate group that agree with the model estimations. The developed model describes general features of the structure of counterion cloud around DNA and is able to predict the number of counterions inside the grooves of the double helix.
