A systematically coarse-grained model for DNA, and its predictions for persistence length, stacking, twist, and chirality

TL;DR

This paper presents a coarse-grained DNA model that captures stereochemistry and physicochemical interactions, predicting properties like persistence length, stacking, twist, and chirality across various conditions.

Contribution

A novel coarse-grained DNA model with anisotropic bases and physicochemical interactions, enabling simulation of structural and mechanical properties under diverse conditions.

Findings

Model predicts phase transitions including unstacking and untwisting.

Captures DNA chirality with stable right-handed and metastable left-handed helices.

Reproduces experimental trends in persistence length and stacking behavior.

Abstract

We introduce a coarse-grained model of DNA with bases modeled as rigid-body ellipsoids to capture their anisotropic stereochemistry. Interaction potentials are all physicochemical and generated from all-atom simulation/parameterization with minimal phenomenology. Persistence length, degree of stacking, and twist are studied by molecular dynamics simulation as functions of temperature, salt concentration, sequence, interaction potential strength, and local position along the chain, for both single- and double-stranded DNA where appropriate. The model of DNA shows several phase transitions and crossover regimes in addition to dehybridization, including unstacking, untwisting, and collapse which affect mechanical properties such as rigidity and persistence length. The model also exhibits chirality with a stable right-handed and metastable left-handed helix.