Premelting effects in DNA under saltfree conditions

Abstract

SynopsisWe have studied the electrical conductivity of NaDNA solutions under "saltfree" conditions a t temperatures well below the melting point of DNA, using radio-frequency dielectric and noise measurements. A conductivity discontinuity is observed at a temperature well below that a t which the usual denaturation processes and trans conformation may commence. The radio-frequency permittivity also exhibits a discontinuity a t the same temperature. For the premelting phase, the conductivity versus temperature curves consist of two linear regions with a change in slope occurring a t 23OC. This effect is related to the behavior of the ionic sheath covering the DNA macromolecule. The activation energy of the alternative current conductivity as well as that the equivalent noise conductivity results as 3.11 kcal/mole below and 4.08 kcal/mole.

Propriétés diélectriques des dispersions de microcristaux de glace : commentaires sur une « mise au point »

“…L'interprétation que nous avons donnée de ces phénomènes [2,4] [44] qui concernent la structure non cristalline des coeurs de dislocation dans la glace. En outre, l'analyse des travaux relatifs aux phénomènes de préfusion dans les cristaux permet de donner un ordre de grandeur comparable pour l'intervalle de température dans lequel se manifestent des anomalies de comportement, à savoir 20 OC environ [45][46][47][48][49][50][51][52][53].…”

Dynamics of K$^+$ counterions around DNA double helix in the external electric field: a molecular dynamics study

“…The dynamics of the ions in water solutions may be characterized by the ionic current that appears under the action of the external electric filed. The experimental studies for DNA in water solution with the different salts of alkali metal ions show that the ionic conductivity essentially depends on the temperature, counterion type and concentration [35][36][37][38][39][40]. The de-pendence of conductivity on counterion type is featured by the ion size, charge and character of hydration [41].…”