Vologodskii A, Cozzarelli N
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Biopolymers. 1995 Mar;35(3):289-96. doi: 10.1002/bip.360350304.
We used a Monte Carlo approach to compute the statistical properties of closed DNA chains with different descriptions of the electrostatic interactions. We compared these computed results with experimentally measured knotting probabilities, which are very sensitive to intersegment interactions. The calculated results based on the Debye-Hückel approximation of the solution of the Poisson-Boltzmann equation agreed very well with the published experimental data, while potential based on counterion condensation theory was clearly less satisfactory. We then compared the simpler hard-core approximation of electrostatic interactions to the Debye-Hückel potential. The hard-core approximation, specified in terms of a DNA effective diameter, gives the same conformational properties of random coils as the Debye-Hückel approximation. We found clear but relatively small differences between the two potentials for the conformational properties of supercoiled DNA.
我们采用蒙特卡罗方法来计算具有不同静电相互作用描述的闭合DNA链的统计特性。我们将这些计算结果与实验测量的打结概率进行了比较，打结概率对链段间相互作用非常敏感。基于泊松 - 玻尔兹曼方程解的德拜 - 休克尔近似计算得到的结果与已发表的实验数据非常吻合，而基于反离子凝聚理论的势显然不太令人满意。然后，我们将静电相互作用的更简单硬核近似与德拜 - 休克尔势进行了比较。根据DNA有效直径指定的硬核近似，给出了与德拜 - 休克尔近似相同的无规卷曲构象性质。我们发现，对于超螺旋DNA的构象性质，这两种势之间存在明显但相对较小的差异。
