Shear unzipping of double stranded DNA

TL;DR

This paper introduces a nonlinear model to analyze shear unzipping of double stranded DNA, predicting the force needed to separate strands and matching experimental data.

Contribution

A simple nonlinear scalar displacement model is developed to accurately predict shear force effects on dsDNA unzipping, including deviations from linear behavior.

Findings

Shear force $F_c$ depends linearly on DNA length for entire strand pulling.

Deviations from linearity occur when parts of the strand move oppositely.

Model predictions agree well with experimental data from Hatch et al.

Abstract

We propose a simple nonlinear scaler displacement model to calculate the distribution of effect created by a shear stress on a double stranded DNA (dsDNA) molecule and the value of shear force $F_c$ which is required to separate the two strands of a molecule. It is shown that as long as the force pulls entire strand in the direction of its application the value of $F_c$ depends linearly on the length; the deviation from linear behaviour takes place when part of a strand moves in opposite direction under the influence of force acting on the other strand. The calculated values of $F_c$ as a function of length of dsDNA molecules are in very good agreement with the experimental values of Hatch et al (Phys. Rev. E $\bf 78$, 011920 (2008)).