THERMODYNAMIC ANALYSIS OF THE INTERACTION OF ACRIDINE DYE PROFLAVINE WITH TETRADEOXYNUCLEOTIDES HAVING DIFFERENT BASE SEQUENCES USING H-1-NMR DATA

The temperature dependence of proton chemical shifts of molecules in aqueous solutions of proflavine with tetradeoxyribonucleoside triphosphates with different base sequences (5'-d (CGCG), 5'-d(GCGC), 5'-d(ACGT), and 5'-d(AGCT)) were studied by 500-MHz NMR spectroscopy. Methods for calculating thermodynamic parameters of complex formation are suggested. They permit the estimation of the differential contributions of reactions leading to the formation of different types of complexes under complex equilibrium conditions. Gibbs free energies, enthalpies, and entropies were determined for the formation of 1:1, 2:1, 1:2, and 2:2 complexes between proflavine and the tetranucleotides.