Effects of static and temporally fluctuating tensions on semiflexible polymer looping

TL;DR

This study investigates how static and fluctuating tensions influence the looping dynamics of semiflexible biopolymers, revealing significant effects on looping times and identifying a resonant activation phenomenon under nonequilibrium tension conditions.

Contribution

It combines Brownian dynamics simulations with analytical theory to explore the impact of static and fluctuating tensions on polymer looping, highlighting the resonant activation effect.

Findings

Minute tension significantly alters looping times for long chains

Resonant activation occurs with dichotomically flipping tension

Results connect with recent experimental observations

Abstract

Biopolymer looping is a dynamic process that occurs ubiquitously in cells for gene regulation, protein folding, etc. In cellular environments, biopolymers are often subject to tensions which are either static, or temporally fluctuating far away from equilibrium. We study the dynamics of semiflexible polymer looping in the presence of such tensions by using Brownian dynamics simulation combined with an analytical theory. We show a minute tension dramatically changes the looping time, especially for long chains. Considering a dichotomically flipping noise as a simple example of the nonequilibrium tension, we find the phenomenon of resonant activation, where the looping time can be the minimum at an optimal flipping time. We discuss our results in connection with recent experiments.