Entropy-driven spatial organization of highly confined polymers: lessons for the bacterial chromosome.
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.
Jun
Suckjoon
S
Stichting voor Fundamenteel Onderzoek der Materie (FOM) Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ, Amsterdam, The Netherlands. jun@amolf.nl
Mulder
Bela
B
D016935:Caulobacter crescentus / Q000235:genetics; D020090:Chromosome Segregation; D002876:Chromosomes, Bacterial / Q000737:chemistry / Q000378:metabolism; D003198:Computer Simulation; D019277:Entropy; D004926:Escherichia coli / Q000235:genetics; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011108:Polymers / Q000737:chemistry / Q000378:metabolism
D011108:Polymers