DNA与组蛋白相互作用的布朗动力学研究

Brownian dynamics simulation of the interaction between DNA and histone

在真核生物中,DNA按左手手征性的方式,缠绕在组蛋白八聚体的周围,形成稳定的核小体结构.文章作者运用布朗动力学,数值模拟了DNA与组蛋白相互作用最终形成核小体的动力学过程,揭示了DNA与组蛋白相互作用的详细图景,并提出了组蛋白八聚体旋转模型,以解释这一过程.文章作者还计算了组成核小体的DNA在受到拉伸力时,组蛋白被从核小体中剥离下来的动力学过程,得到了组装和剥离过程的详细图像,给出了与前人单分子实验一致的拉伸力与拉伸长度的关系曲线和拉伸台阶.此外,还通过建立的组蛋白手征性模型,模拟了核小体手征性的形成过程,发现DNA的缠绕方向强烈依赖于组蛋白的手征性,显示出环境温度对核小体手征性有重要影响.

In all eukaryotes, DNA wraps around a histone octamer in a left - handed way, forming a stable nucleosome structure. We numerically study the interaction between DNA and histone using a Brownian dynamics simulation. The process of nucleosome formation is shown in detail. We propose a histone octamer rotation model for the process of nucleosome formation. By simulating the stretching of a nucleosome chain we obtain the force versus extension and extension versus time curves, which are found to be consistent with experimental results. The process of chirality formation of a nucleosome is studied by building up a histone octamer model with a quantitatively adjustable chirality, and the chirality is found to be strongly dependent on the chirality of the histone octamer. We also show that the nucleosome chirality may be broken at elevated temperatures.