Semenov A N, Nyrkova I A
Institut Charles Sadron, CNRS - UPR 22, Université de Strasbourg, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France.
Soft Matter. 2024 Jun 5;20(22):4366-4388. doi: 10.1039/d4sm00188e.
We theoretically study pairing (double-strand complexation) of semiflexible wormlike chains (WLC) due to their side-to-side attraction. Considering binding of two WLCs of high stiffness we start with the case of infinite stiffness of one chain which is replaced with a straight bar. A combination of the quantitative transfer matrix approach with scaling arguments in terms of trains, loops of different sizes, tails and supertrains allowed us to characterize all the regimes of semiflexible chain adsorption on a bar. In particular, we predict a self-similar monomer concentration profile () ∝ near the bar (at distances below the chain Kuhn length ) at the critical point for adsorption. Such localized critical profile leads to a sharp adsorption transition. Furthermore, we found that supertrains serve as the basic structural elements in WLC complexes leading to bridging, network formation and condensation of semiflexible polymers in dilute solutions. Polymer collapse (precipitation) and redissolution on increasing attraction strength are predicted in qualitative agreement with experiments on aqueous solutions of DNA and F-actin.
我们从理论上研究了半柔性蠕虫状链（WLC）由于其侧向吸引力而形成的配对（双链复合）现象。考虑到两条高刚性WLC的结合，我们从一条链具有无限刚性的情况开始，这条链被替换为一根直杆。定量转移矩阵方法与基于不同大小的链段、环、尾以及超链段的标度论证相结合，使我们能够描述半柔性链在杆上吸附的所有状态。特别地，我们预测在吸附临界点，靠近杆处（在距离小于链的库恩长度处）单体浓度分布呈自相似形式（）∝ 。这种局部临界分布导致了尖锐的吸附转变。此外，我们发现超链段是WLC复合物中的基本结构单元，导致稀溶液中半柔性聚合物的桥连、网络形成和凝聚。预测了随着吸引力强度增加聚合物的塌缩（沉淀）和再溶解，这与DNA和F - 肌动蛋白水溶液的实验定性一致。
