Comments on "Length scale dependence of DNA mechanical properties"

TL;DR

This paper critiques recent claims that DNA's mechanical properties deviate from the wormlike rod model at short lengths, arguing that the data analysis in those claims was flawed and that the traditional model remains valid.

Contribution

It clarifies the correct interpretation of molecular dynamics simulation data, reaffirming the validity of the wormlike rod model for DNA at short length scales.

Findings

Previous data analysis was incorrect

Earlier conclusions about DNA rigidity are valid

No detectable deviations from the wormlike rod model

Abstract

Recent experimental data indicate that the elastic wormlike rod model of DNA that works well on long length scales may break down on shorter scales relevant to biology. According to Noy and Golestanian (Phys. Rev. Lett. 109, 228101, 2012) molecular dynamics (MD) simulations predict DNA rigidity close to experimental data and confirm one scenario of such breakdown, namely, that for lengths of a few helical turns, DNA dynamics exhibit long-range bending and stretching correlations. Earlier studies using similar forcefields concluded that (i) MD systematically overestimate the DNA rigidity, and (ii) no deviations from the WLR model are detectable. Here it is argued that the data analysis in the above mentioned paper was incorrect and that the earlier conclusions are valid.