STUDY OF DNA INTERACTIONS WITH Cu<sup>2+</sup> AND Mg<sup>2+</sup> IONS IN THE PRESENCE OF CAFFEINE
A study is presented of caffeine effects on the complexation of the DNA molecule with Cu<sup>2+</sup> and Mg<sup>2+</sup> ions in solution. DNA binding with cations and caffeine is captured from changes in DNA circular dichroism and UV absorption spectra. The complexation of caffeine with M<sup>2+</sup> ions is studied by IR spectroscopy. Caffeine is found to form complexes of different structure with Mg<sup>2+</sup> and Cu<sup>2+</sup> ions in solution. In the presence of caffeine, DNA solutions with MCl<sub>2</sub> show signs of formation of intricate complexes involving nitrogenous bases. In DNA solutions with CuCl<sub>2</sub>, the presence of caffeine causes additional destabilization of the secondary DNA structure. In DNA solutions with MgCl<sub>2</sub>, the presence of caffeine leads to the formation of new complexes with the participation of Mg<sup>2+</sup>, caffeine, and bases without disrupting the secondary DNA structure.