Comment on "Flexibility of short DNA helices with finite-length effect: From base pairs to tens of base pairs"

TL;DR

This paper derives an empirical formula for DNA persistence length from atomistic simulations, showing it can be explained by a non-local twistable wormlike chain model and applies broadly to polymers with non-local couplings.

Contribution

It provides a theoretical derivation of Wu et al.'s empirical formula using a non-local polymer model, extending its applicability to torsional persistence length and other polymers.

Findings

The empirical formula is derived from a non-local twistable wormlike chain model.

The formula explains the length-dependent increase in DNA persistence length.

It is applicable to various polymers with non-local interactions.

Abstract

While analyzing the persistence length of DNA atomistic simulations Wu et al. [J. Chem. Phys. 142, 125103 (2015)] introduced an empirical formula to account for the observed length-dependence. In particular they found that the persistence length increases with the distance. Here, we derive the formula by Wu et al. using a non-local twistable wormlike chain which introduces couplings between distal sites. Finally, we show that the same formula can account for the length-scale dependence of the torsional persistence length and is, in fact, applicable to any kind of polymer model with non-local couplings.