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arXiv 2103.05703cond-mat.softcond-mat.stat-mechphysics.comp-ph
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纽结是半柔性聚合物中的一类稳定相

Knots are Generic Stable Phases in Semiflexible Polymers

Suman Majumder, Martin Marenz, Subhajit Paul, Wolfhard Janke

摘要:

半柔性聚合物模型被广泛用作理解生物分子中的结构相的范例,包括蛋白质的折叠。由于稳定结在真实蛋白质中并不常见,因此半柔性聚合物中稳定结的存在还没有被探索太多。在这里,通过广泛的副本交换蒙特卡罗模拟,我们调查相同的珠棒和珠弹簧均聚物模型,涵盖了整个范围从灵活到僵硬。我们建立的事实是,在相图中的稳定的打结相的存在是依赖于比例$r_b/r_{\rm{min}}$,其中$r_b$是平衡键长和$r_{\rm{min}}$是最强的非键合接触的距离。我们的研究结果为两种模型提供了证据,即如果比率$r_b/r_{\rm{min}}$在一个小窗口之外,则取决于弯曲刚度,在低温下总是遇到稳定的打结相以及通常的冻结和类似的结构。这些发现促使我们得出结论,结是半柔性聚合物中的通用稳定相。

英文摘要:

Semiflexible polymer models are widely used as a paradigm to understand structural phases in biomolecules including folding of proteins. Since stable knots are not so common in real proteins, the existence of stable knots in semiflexible polymers has not been explored much. Here, via extensive replica exchange Monte Carlo simulation we investigate the same for a bead-stick and a bead-spring homopolymer model that covers the whole range from flexible to stiff. We establish the fact that the presence of stable knotted phases in the phase diagram is dependent on the ratio $r_b/r_{\rm{min}}$ where $r_b$ is the equilibrium bond length and $r_{\rm{min}}$ is the distance for the strongest nonbonded contacts. Our results provide evidence for both models that if the ratio $r_b/r_{\rm{min}}$ is outside a small window around unity then depending on the bending stiffness one always encounters stable knotted phases along with the usual frozen and bent-like structures at low temperatures. These findings prompt us to conclude that knots are generic stable phases in semiflexible polymers.

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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