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

摘要

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