The 3-dimensional random walk with applications to overstretched DNA and the protein titin

TL;DR

This paper introduces a simple 3D persistent random walk model with drift, providing a thermodynamic framework that accurately describes polymer stretching experiments like DNA overstretching and titin elasticity.

Contribution

It develops a novel thermodynamic model based on a 3D persistent random walk without assuming Boltzmann-Gibbs distribution, enabling closed-form calculations for polymer behavior.

Findings

Model accurately describes DNA overstretching transition.

Reproduces static force-extension relation of titin.

Provides a unified framework for different polymer stretching experiments.

Abstract

We study the three-dimensional persistent random walk with drift. Then we develop a thermodynamic model that is based on this random walk without assuming the Boltzmann-Gibbs form for the equilibrium distribution. The simplicity of the model allows us to perform all calculations in closed form. We show that, despite its simplicity, the model can be used to describe different polymer stretching experiments. We study the reversible overstretching transition of DNA and the static force-extension relation of the protein titin.