The Storm and Nelson's model for polymer stretching revisited

TL;DR

This paper revisits the Storm and Nelson's model for DNA stretching, providing a clear physical understanding and successful fitting of experimental data through the cavity method, enhancing the modeling of single molecule mechanics.

Contribution

It offers a refined phenomenological model for DNA stretching, solved via the cavity method, with validated fits to experimental data and Monte Carlo simulations.

Findings

Model accurately reproduces DNA stretching behavior

Properties like bending stiffness are clearly derived

Theoretical results match experimental measurements

Abstract

The quite recent technological rise in molecular biology allowed single molecule manipulation experiments, where molecule stretching plays a primary role. In order to understand the experimental data, it is felt the urge of some physical and mathematical models to quantitatively express the mechanical properties of the observed molecules. In this paper we reconsider a simple phenomenological model which reproduces the behaviour of single and double stranded DNA under tension. The problem is easily solved via the cavity method both in the small forces range and in presence of overstretching transition, so that some properties such as bending stiffness and elasticity of DNA emerge in a very clear manner. Our theoretical findings are successfully fitted to real measurements and compared to Monte Carlo simulations, confirming the quality of the approach.