Stretching An Anisotropic DNA

TL;DR

This paper develops a perturbation theory to analyze how anisotropic DNA responds to external tension, revealing that anisotropy has a minor effect on its force-extension behavior, which can be approximated by an isotropic model with an effective bending constant.

Contribution

It introduces a perturbation approach to quantify the impact of anisotropy on DNA elasticity, simplifying the model to an effective isotropic behavior.

Findings

Anisotropy contributes a small correction to the force-extension curve.

DNA behaves approximately as isotropic with an effective bending constant.

Effective bending constant is the harmonic average of soft and hard bending constants.

Abstract

We present a perturbation theory to find the response of an anisotropic DNA to the external tension. It is shown that the anisotropy has a nonzero but small contribution to the force-extension curve of the DNA. Thus an anisotropic DNA behaves like an isotropic one with an effective bending constant equal to the harmonic average of its soft and hard bending constants.