Increase of cationic concentration due to bending of overcharged DNA in strong Coulomb coupling regime

TL;DR

This paper demonstrates that bending overcharged DNA in strong Coulomb coupling conditions causes some counterions to be released, yet the DNA remains overcharged, impacting theoretical models of DNA ionic interactions.

Contribution

It reveals a novel phenomenon where bending overcharged DNA releases counterions, affecting the understanding of DNA stability in strong Coulomb coupling regimes.

Findings

Bending overcharged DNA releases some adsorbed counterions.

DNA remains fully overcharged after bending.

This phenomenon influences ionic concentration models for DNA.

Abstract

This study reveals that, in strong coulomb coupling regime, bending a straight and fully overcharged DNA (up to its maximal acceptance by multivalent counterions) to a circle releases some of the adsorbed (correlated)counterions but still remains fully overcharged. This phenomenon seems to be inherent to the minimum energy state of a DNA. By definition, the total electrostatic potential energy of a macroion-counterion system reaches to its lowest point at maximal acceptance of overcharging counterions that ensures the most stable conformation. This intermediate phenomenon of release of cations from DNA surface due to bending can be taken into account in theoretical modeling of some ionic concentration dependent physico-chemical aspects of DNA solutions in strong Coulomb coupling regimes.