Unzipping DNA by force: thermodynamics and finite size behaviour

TL;DR

This paper analyzes the thermodynamics of DNA unzipping under force, focusing on finite size effects and phase diagrams, with implications for experimental determination of DNA's thermodynamic properties.

Contribution

It introduces a finite size scaling approach to extract DNA phase diagrams from unzipping experiments, considering different thermodynamic ensembles.

Findings

Finite size scaling reveals the phase transition characteristics.

The Y-fork is identified as a coexisting phase in fixed distance ensemble.

Procedures proposed can help determine thermodynamic phase diagrams experimentally.

Abstract

We discuss the thermodynamic behaviour near the force induced unzipping transition of a double stranded DNA in two different ensembles. The Y-fork is identified as the coexisting phases in the fixed distance ensemble. From finite size scaling of thermodynamic quantities like the extensibility, the length of the unzipped segment of a Y-fork, the phase diagram can be recovered. We suggest that such procedures could be used to obtain the thermodynamic phase diagram from experiments on finite length DNA.