Can a double stranded DNA be unzipped by pulling a single strand?: Phases of adsorbed DNA

TL;DR

This paper investigates the unzipping behavior of double stranded DNA when pulling on a single strand, revealing phase diagrams that differ from traditional methods and are significantly affected by surface interactions.

Contribution

It introduces a detailed phase diagram for single-strand unzipping of DNA and explores how surface attraction alters DNA unzipping behavior.

Findings

DNA can be unzipped by pulling a single strand above a critical force

Phase diagram differs from unzipping by pulling both strands

Surface attraction introduces critical end points and triple points

Abstract

We study the unzipping of a double stranded DNA (dsDNA) by applying an external force on a single strand while leaving the other strand free. We find that the dsDNA can be unzipped to two single strands if the external force exceeds a critical value. We obtain the phase diagram which is found to be different from the phase diagram of unzipping by pulling both the strands in opposite directions. In the presence of an attractive surface near DNA, the phase diagram gets modified drastically and shows richer surprises including a critical end point and a triple point.