Modeling the effect of intercalators on the high-force stretching behavior of DNA

TL;DR

This paper introduces a statistical model that explains how intercalators influence DNA's force-extension behavior, predicting a new hyper-stretching regime and a linear relationship between overstretching force and intercalator concentration.

Contribution

The study provides a novel statistical model that captures experimental findings and predicts new behaviors of intercalated DNA under force.

Findings

Prediction of a hyper-stretching regime in intercalated DNA

Verification of linear dependence of overstretching force on intercalator concentration

Model accurately reproduces recent experimental force-extension data

Abstract

DNA is structurally and mechanically altered by the binding of intercalator molecules. Intercalation strongly affects the force-extension behavior of DNA, in particular the overstretching transition. We present a statistical model that captures all relevant findings of recent force-extension experiments. Two predictions from our model are presented. The first suggests the existence of a novel hyper-stretching regime in the presence of intercalators and the second, a linear dependence of the overstretching force on intercalator concentration, is verified by re-analyzing available experimental data. Our model pins down the physical principles that govern intercalated DNA mechanics, providing a predictive understanding of its limitations and possibilities.