STUDY OF DNA INTERACTIONS WITH Cu2+ AND Mg2+ IONS IN THE PRESENCE OF CAFFEINE
S. V. Paston, A. M. Polyanichko, O. V. Shulenina
St. Petersburg State University, St. Petersburg, Russia
Keywords: ДНК, кофеин, ионы металлов, УФ поглощение, круговой дихроизм, ИК спектроскопия, вторичная структура ДНК, DNA, caffeine, metal ions, UV absorption, circular dichroism, IR spectroscopy, DNA secondary structure
Abstract
A study is presented of caffeine effects on the complexation of the DNA molecule with Cu2+ and Mg2+ 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 M2+ ions is studied by IR spectroscopy. Caffeine is found to form complexes of different structure with Mg2+ and Cu2+ ions in solution. In the presence of caffeine, DNA solutions with MCl2 show signs of formation of intricate complexes involving nitrogenous bases. In DNA solutions with CuCl2, the presence of caffeine causes additional destabilization of the secondary DNA structure. In DNA solutions with MgCl2, the presence of caffeine leads to the formation of new complexes with the participation of Mg2+, caffeine, and bases without disrupting the secondary DNA structure.
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