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arXiv 0905.0798cond-mat.softcond-mat.stat-mech
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致密聚合物的构象性质

Conformational properties of compact polymers

Manfred Bohn, Dieter W. Heermann

摘要:

粗粒聚合物的蒙特卡罗模拟为加深对聚合物在物理和生物体系中的构象和统计性质的理解提供了一个有用的工具。在这项研究中,我们采样紧凑的构象上的立方LxLxL晶格不同的占有率通过修改最近提出的算法。研究的系统尺寸扩展到N=256000单体,远远超出了紧凑的聚合物上的旧出版物的限制。我们分析了这些聚合物的几种构象性质,包括片段相关性和排除体积的筛选。最重要的是,我们提出了一个缩放律的端到端的距离分布,并分析了这个分布的时刻。它显示了相对于不同的占有率,即系统密度的普遍性。我们进一步分析了链内片段之间的距离分布,这对生物实验具有重要意义。我们将这些新的发现应用于间期核内染色质折叠的问题,并表明-虽然染色质是在一个紧凑的状态-紧凑的聚合物的经典理论不能解释最近的实验结果。

英文摘要:

Monte Carlo simulations of coarse-grained polymers provide a useful tool to deepen the understanding of conformational and statistical properties of polymers both in physical as well as in biological systems. In this study we sample compact conformations on a cubic LxLxL lattice with different occupancy fractions by modifying a recently proposed algorithm. The system sizes studied extend up to N=256000 monomers, going well beyond the limits of older publications on compact polymers. We analyze several conformational properties of these polymers, including segment correlations and screening of excluded volume. Most importantly we propose a scaling law for the end-to-end distance distribution and analyze the moments of this distribution. It shows universality with respect to different occupancy fractions, i.e. system densities. We further analyze the distance distribution between intrachain segments, which turns out to be of great importance for biological experiments. We apply these new findings to the problem of chromatin folding inside interphase nuclei and show that -- although chromatin is in a compacted state -- the classical theory of compact polymers does not explain recent experimental results.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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