Condensation of DNA-actin polyelectrolyte mixtures driven by ions of different valences.
Condensation of DNA-actin polyelectrolyte mixtures driven by ions of different valences.
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DOI：
10.1103/physreve.73.031911
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发表时间：
2006-03
期刊：
影响因子：
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通讯作者：
Olena V. Zribi;Hee Kyung;R. Golestanian;T. Liverpool;G. Wong
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文献类型：
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作者：
Olena V. Zribi;Hee Kyung;R. Golestanian;T. Liverpool;G. Wong
多价离子可以诱导相同电荷的聚电解质凝聚成致密状态，这一过程需要对不同的聚电解质物种使用不同的离子价态。在这项工作中，我们研究了由DNA线圈和F-肌动蛋白棒组成的二元阴离子聚电解质混合物在一价、二价和三价离子存在下的缩合行为。正如预期的那样，一价离子不会凝聚任何一种成分，而二价离子选择性地凝聚聚电解质混合物中的F-肌动蛋白棒。然而，对于三价离子，我们观察到两种聚电解质之间存在微相分离，形成共存的有限大小的F-肌动蛋白束和DNA环状结构。此外，通过增加DNA在混合物中的体积分数，凝聚的F-肌动蛋白束可以完全不稳定，导致只有DNA在混合物中凝聚。我们研究了一些可能的原因，并提出了一个基于聚电解质对离子竞争的模型。
Multivalent ions can induce condensation of like-charged polyelectrolytes into compact states, a process that requires different ion valences for different polyelectrolyte species. In this work we examine the condensation behavior in binary anionic polyelectrolyte mixtures consisting of DNA coils and F-actin rods in the presence of monovalent, divalent, and trivalent ions. As expected, monovalent ions do not condense either component and divalent ions selectively condense F-actin rods out of the polyelectrolyte mixture. For trivalent ions, however, we observe a microphase separation between the two polyelectrolytes into coexisting finite-sized F-actin bundles and DNA toroids. Further, by increasing the DNA volume fraction in the mixture, condensed F-actin bundles can be completely destabilized, leading to only DNA condensation within the mixture. We examine a number of possible causes and propose a model based on polyelectrolyte competition for ions.