An. Veselkov et al., THERMODYNAMIC ANALYSIS OF ETHIDIUM-BROMIDE INTERACTION WITH DEOXYTETRARIBONUCLEOTIDE 5'-D(CPGPCPG) IN AQUEOUS-SOLUTIONS BASED ON THE H-1-NMR DATA, CHEMICAL PHYSICS REPORTS, 16(4), 1997, pp. 745-757
Temperature dependences of chemical shifts of protons of ethidium brom
ide mixed with aqueous solution of self-complementary deoxytetraribonu
cleosidetriphosphate 5'-d(CpGpCpG) are measured using a pulse NMR spec
trometer (500 MHz). The applied procedures for calculating thermodynam
ic parameters enabled us to separate the contributions of different re
actions to the overall heat of complexation at equilibrium between var
ious species formed in aqueous solutions. Mole fractions of aggregates
are calculated as functions of temperature. Free Gibbs energies, enth
alpies, and entropies of formation of 1:1, 2:1, 1:2, and 2:2 complexes
between ethidium bromide and tetranucleotide are estimated. A compara
tive thermodynamic analysis of complexation of acridine dye (proflavin
e) and ethidium bromide with 5'-d(CpGpCpG) under identical experimenta
l conditions is accomplished.