Subdiffusive motion of a polymer composed of subdiffusive monomers

Abstract

We use Brownian dynamics simulations and analytical theory to investigate the physical principles underlying subdiffusive motion of a polymer. Specifically, we examine the consequences of confinement, self-interaction, viscoelasticity, and random waiting on monomer motion, as these physical phenomena may be relevant to the behavior of biological macromolecules in vivo. We find that neither confinement nor self-interaction alter the fundamental Rouse mode relaxations of a polymer. However, viscoelasticity, modeled by fractional Langevin motion, and random waiting, modeled with a continuous time random walk, lead to significant and distinct deviations from the classic polymer-dynamics model. Our results provide diagnostic tools--the monomer mean square displacement scaling and the velocity autocorrelation function--that can be applied to experimental data to determine the underlying mechanism for subdiffusive motion of a polymer.