Entropy-driven spatial organization of highly confined polymers: Lessons for the bacterial chromosome
Entropy-driven spatial organization of highly confined polymers: Lessons for the bacterial chromosome
复制标题
DOI：
10.1073/pnas.0605305103
复制
发表时间：
2006-08-15
影响因子：
11.1
通讯作者：
Mulder, Bela
中科院分区：
文献类型：
--
作者：
Jun, Suckjoon;Mulder, Bela
尽管可视化实验最近取得了进展，但细菌染色体分离的机制仍然难以捉摸。在这里，我们解决了与细菌染色体分离相关的基本物理问题，即棒状细胞几何形状中高度受限、自我回避的聚合物（具有非平凡的拓扑结构）的空间组织。通过计算机模拟，我们提供的证据表明，在强限制条件下，聚合物复合物的拓扑不同的域有效地相互排斥，以最大化其构象熵，这表明重复的环状染色体可以自发分裂。这种机制不仅能够解释空间分离本身，而且还捕获了在大肠杆菌和新月柄杆菌中观察到的复制染色体时空组织的主要特征。
Despite recent progress in visualization experiments, the mechanism underlying chromosome segregation in bacteria still remains elusive. Here we address a basic physical issue associated with bacterial chromosome segregation, namely the spatial organization of highly confined, self-avoiding polymers (of nontrivial topology) in a rod-shaped cell-like geometry. Through computer simulations, we present evidence that, under strong confinement conditions, topologically distinct domains of a polymer complex effectively repel each other to maximize their conformational entropy, suggesting that duplicated circular chromosomes could partition spontaneously. This mechanism not only is able to account for the spatial separation per se but also captures the major features of the spatiotemporal organization of the duplicating chromosomes observed in Escherichia coli and Caulobacter crescentus.