Stretching of long double-stranded DNA and RNA described by the same model.

Abstract

We propose a bead-spring model that accurately reproduces a variety of experimental force-extension curves of long double-stranded DNA and RNA, including torsionally constrained and unconstrained DNA, and negatively supercoiled DNA. A key feature of the model is a specific non-convex energy function of the spring. We provide an algorithm for obtaining five required parameters of the model from experimental force-extension curves. In the plateau region of the force-extension curves, our molecular dynamics simulations show that the polymer separates into a mix of weakly and strongly stretched states without forming macroscopically distinct phases.