Monomer dynamics of a wormlike chain

TL;DR

This paper derives analytical equations describing the motion of a tracer attached to a semiflexible polymer, aiding the analysis of single-molecule experiments and protein fluctuations.

Contribution

It provides explicit analytical expressions for the stochastic dynamics of a tracer on a wormlike chain derived from microscopic equations.

Findings

Explicit Langevin equation for tracer dynamics

Power spectrum and mean-square displacement formulas

Applicable to experimental analysis of protein shape fluctuations

Abstract

We derive the stochastic equations of motion for a tracer that is tightly attached to a semiflexible polymer and confined or agitated by an externally controlled potential. The generalised Langevin equation, the power spectrum, and the mean-square displacement for the tracer dynamics are explicitly constructed from the microscopic equations of motion for a weakly bending wormlike chain by a systematic coarse-graining procedure. Our accurate analytical expressions should provide a convenient starting point for further theoretical developments and for the analysis of various single-molecule experiments and of protein shape fluctuations.