Thermally stimulated electric changes during the helix to coil transition of irradiated DNA

The purpose of the present work was to investigate early changes evolved in the DNA macromolecule during its helix to coil phase transition following exposure to ionizing radiation. This phase transition measures the thermostability of this macromolecule and it is greatly affected by exposure to ionizing radiations apparently due to induced single strand and double strand breaks on either or the two coils of the double DNA helix. Our results indicate that conductivity changes definitely preceding the helix to coil transition. This observation is on line with the suggested precedence of hydrophobic bonds disruption prior to hydrogen bonds disruption which coincides with this type of phase transition that finally leads to the denaturation of the DNA