Statistical Physics of Unzipping DNA

TL;DR

This paper models the unzipping of DNA using statistical physics, revealing how force, temperature, and sequence heterogeneity influence the denaturation process and unzipping dynamics.

Contribution

It introduces a theoretical framework connecting DNA unzipping behavior with statistical physics, explaining experimental observations and energy barrier scaling.

Findings

Sequence heterogeneity affects force-extension curves.

Unzipping exhibits anomalous drift and diffusion.

Energy barriers scale with the square root of genome size.

Abstract

The denaturation of double-stranded DNA as function of force and temperature is discussed. At room temperature, sequence heterogeneity dominates the physics of single molecule force-extension curves starting about 7 piconewtons of below a ~15 pN unzipping transition. The dynamics of the unzipping fork exhibits anomalous drift and diffusion in a similar range above this transition. Energy barriers near the transition scale as the square root of the genome size. Recent observations of jumps and plateaus in the unzipping of lambda phage DNA at constant force are consistent with these predictions.