Issue 11, 2017

The effect of active fluctuations on the dynamics of particles, motors and DNA-hairpins

Abstract

Inspired by recent experiments on the dynamics of particles and polymers in artificial cytoskeletons and in cells, we introduce a modified Langevin equation for a particle in an environment that is a viscoelastic medium and that is brought out of equilibrium by the action of active fluctuations caused by molecular motors. We show that within such a model, the motion of a free particle crosses over from superdiffusive to subdiffusive as observed for tracer particles in an in vitro cytoskeleton or in a cell. We investigate the dynamics of a particle confined by a harmonic potential as a simple model for the motion of the tethered head of kinesin-1. We find that the probability that the head is close to its binding site on the microtubule can be enhanced by a factor of two due to active forces. Finally, we study the dynamics of a particle in a double well potential as a model for the dynamics of DNA-hairpins. We show that the active forces effectively lower the potential barrier between the two minima and study the impact of this phenomenon on the zipping/unzipping rate.

Graphical abstract: The effect of active fluctuations on the dynamics of particles, motors and DNA-hairpins

Supplementary files

Article information

Article type
Paper
Submitted
14 Nov 2016
Accepted
20 Feb 2017
First published
21 Feb 2017

Soft Matter, 2017,13, 2181-2191

The effect of active fluctuations on the dynamics of particles, motors and DNA-hairpins

H. Vandebroek and C. Vanderzande, Soft Matter, 2017, 13, 2181 DOI: 10.1039/C6SM02568D

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