2014/01/03 by O. O. Liubysh, Liubysh, O. O., О. М. Alekseev +5
Biochemistry, Genetics and Molecular Biology · Engineering · #Advanced biosensing and bioanalysis techniques #Biological Physics (physics.bio-ph) #Biomolecules (q-bio.BM) #DNA and Nucleic Acid Chemistry #FOS: Biological sciences #FOS: Physical sciences #Nanopore and Nanochannel Transport Studies #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.1401.0606
openalex publication_date 2014/01/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The effects of ionic ordering in DNA water solutions are studied by conductivity experiments. The conductivity measurements are performed for the solutions of DNA with KCl salt in the temperature range from 28 to 70 C. Salt concentration vary from 0 to 2 M. The conductivity of solutions without DNA but with the same concentration of KCl salt are also performed. The results show that in case of salt free solution of DNA the melting process of the double helix is observed, while in case of DNA solution with added salt the macromolecule denaturation is not featured. For salt concentrations lower than some critical one (0.4 M) the conductivity of DNA solution is higher than the conductivity of KCl water solution without DNA. Starting from the critical concentration the conductivity of KCl solution is higher than the conductivity of DNA solution with added salt. For description of the experimental data phenomenological model is elaborated basing on electrolyte theory. In framework of the developed model a mechanism of counterion ordering is introduced. According to this mechanism under the low salt concentrations electrical conductivity of the system is caused by counterions of DNA ion-hydrate shell. Increasing the amount of salt to the critical concentration counterions condense on DNA polyanion. Further increase of salt concentration leads to the formation of DNA-salt complexes that decreases the conductivity of the system.