Ion dynamics and water percolation effects in DNA polymorphism
Ion dynamics and water percolation effects in DNA polymorphism
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DOI：
10.1021/ja0732882
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发表时间：
2008-01-09
影响因子：
15
通讯作者：
Mazur, Alexey K.
中科院分区：
文献类型：
--
作者：
Brovchenko, Ivan;Krukau, Aliaksei;Mazur, Alexey K.
通过计算机模拟研究了DNA表面离子和水的动力学，涉及DNA中低水合多态性区的广泛水合作用。离子的远程迁移率在三个不同的水合水平下呈现逐步增加。其中第一个接近水渗透过渡的中点以及A-和B-DNA形式之间过渡的中点。这与DNA表面上的离子对的解离的开始相一致，这可能是由于跨越氢键网络的出现而引起的水介电常数的增加。另外两个步骤是由于在DNA表面上形成亲水层，伴随着离子从DNA表面的逐渐逃逸。结果与早期的实验数据一致，并进一步证实了所建议的普遍机制的低水合多态性的DNA，包括双链内静电凝聚接近水渗透阈值。
The dynamics of ions and water at the surface of DNA are studied by computer simulations in a wide range of hydrations involving the zone of low-hydration polymorphism in DNA. The long-range mobility of ions exhibits a stepwise increase at three distinct hydration levels. The first of them is close to the midpoint of the water percolation transition as well as the midpoint of the transition between A- and B-DNA forms. It coincides with the onset of the dissociation of ion pairs on the DNA surface probably caused by the increase in the water dielectric permittivity due to the appearance of the spanning hydrogen-bonding network. The other two steps are attributed to the formation of percolating water layers on the surface of DNA accompanied by the progressive escape of ions from the DNA surface. The results agree with earlier experimental data and further corroborate the suggested universal mechanism of the low hydration polymorphism in DNA including intraduplex electrostatic condensation close to the water percolation threshold.