Thermomechanical Stability and Mechanochemical Response of DNA: a Minimal Mesoscale Model

TL;DR

This paper introduces a minimal mesoscale model that accurately predicts the thermomechanical and mechanochemical behavior of homogeneous DNA under various mechanical stresses, aligning well with experimental data.

Contribution

The study presents a simple yet effective mesoscale model capturing DNA's thermomechanical responses, including denaturation and overstretching phenomena, with strong experimental validation.

Findings

Predicted critical temperatures for DNA denaturation under torque and stretch.

Mapped phase diagrams for stable DNA configurations.

Explained the smooth overstretching transition through criticality proximity.

Abstract

We show that a mesoscale model, with a minimal number of parameters, can well describe the thermomechanical and mechanochemical behavior of homogeneous DNA at thermal equilibrium under tension and torque. We predict critical temperatures for denaturation under torque and stretch, phase diagrams for stable DNA, probe/response profiles under mechanical loads, and the density of dsDNA as a function of stretch and twist. We compare our predictions with available single molecule manipulation experiments and find strong agreement. In particular we elucidate the difference between angularly constrained and unconstrained overstretching. We propose that the smoothness of the angularly constrained overstreching transition is a consequence of the molecule being in the vicinity of criticality for a broad range of values of applied tension.