English

Uniform description of polymer ejection dynamics from capsid with and without hydrodynamics

Biological Physics 2017-06-07 v2

Abstract

We use stochastic rotation dynamics to examine the dynamics of the ejection of an initially strongly confined flexible polymer from a spherical capsid with and without hydrodynamics. The results obtained using SRD are compared to similar Langevin simulations. Inclusion of hydrodynamic modes speeds up the ejection but also allows the part of the polymer outside the capsid to expand closer to equilibrium. This shows as higher values of radius of gyration when hydrodynamics are enabled. By examining the waiting times of individual polymer beads we find that the waiting time twt_w grows with the number of ejected monomers ss as a sum of two exponents. When 63%\approx 63 \% of the polymer has ejected the ejection enters the regime of slower dynamics. The functional form of twt_w vs ss is universal for all ejection processes starting from the same initial monomer densities. Inclusion of hydrodynamics only reduces its magnitude. Consequently, we define a universal scaling function hh such that the cumulative waiting time t=N0h(s/N0)t = N_0 h(s/N_0) for large N0N_0. Our unprecedently precise measurements of force indicate that this form for tw(s)t_w(s) originates from the corresponding force towards the pore decreasing super exponentially at the end of the ejection. Our measured tw(s)t_w(s) explains the apparent superlinear scaling of the ejection time with the polymer length for short polymers. However, for asymptotically long polymers tw(s)t_w(s) predicts linear scaling.

Keywords

Cite

@article{arxiv.1702.03867,
  title  = {Uniform description of polymer ejection dynamics from capsid with and without hydrodynamics},
  author = {Joonas Piili and Pauli M. Suhonen and Riku P. Linna},
  journal= {arXiv preprint arXiv:1702.03867},
  year   = {2017}
}

Comments

12 pages 26 figures

R2 v1 2026-06-22T18:17:06.055Z