Electric Field of DNA in Solution: Who Is in Charge?

作者：Jonathan G. Hedley, Kush Coshic, Aleksei Aksimentiev, Alexei A. Kornyshev · 发表于：Physical Review X · 年份：2024 · DOI：10.1103/physrevx.14.031042 · 被引用次数：17 · 研究领域：Electrostatics and Colloid Interactions、Nanopore and Nanochannel Transport Studies、DNA and Nucleic Acid Chemistry

In solution, DNA, the "most important molecule of life," is a highly charged macromolecule that bears a unit of negative charge on each phosphate of its sugar-phosphate backbone. Although partially compensated by counterions (cations of the solution) adsorbed at or condensed near it, DNA still produces a substantial electric field in its vicinity, which is screened by buffer electrolytes at longer distances from the DNA. This electric field is experienced by any charged or dipolar species approaching and interacting with the DNA. So far, such a field has been explored predominantly within the scope of a primitive model of the electrolytic solution, not considering more complicated structural effects of the water solvent. In this paper, we investigate the distribution of electric field around DNA using linear response nonlocal electrostatic theory, applied here for helix-specific charge distributions, and compare the predictions of such a theory with specially performed, fully atomistic, large-scale, molecular dynamics simulations. Both approaches are applied to unravel the role of the structure of water at close distances to and within the grooves of a DNA molecule in the formation of the electric field. As predicted by the theory and reported by the simulations, the main finding of this study is that oscillations in the electrostatic potential distribution are present around DNA, caused by the overscreening effect of structured water. Surprisingly, electrolyte ions at physio...