Thermodynamic Parameters of Binding of Small Molecules to DNA Irradiated by Low-Intensity Millimeter Electromagnetic Waves

The interaction of biologically active molecules (BAM) with the biopolymer DNA, which performs the most important functions in a living organism having a double helical structure, irradiated with non-thermal electromagnetic millimeter waves, has been studied. It has been shown, that BAM (doxorubicin, mitoxantrone, and netropsin) form more stable complexes with DNA irradiated with the resonant frequencies of natural vibrations of the molecular structures of water (64.5 and 50.3 GHz). Under the influence of the above non-thermal millimeter waves, dehydration of the DNA molecule occurs, which leads to an increase in the binding constant of BAM to irradiated DNA. Calculations show that as a result of irradiation, the thermodynamic parameters of the binding of BAM to DNA change-enthalpy (ΔH) and entropy (ΔS): For all studied BAM, ΔH < 0, and ΔS > 0. The greatest change in entropy occurs for netropsin that binds externally to DNA.