Biopolymers and cell. 1995; 11 (5): 37 - 45

THERMODYNAMICS OF PHENANTRIDINIUM DYE ETHIDIUM BROMIDE INTERACTION WITH DEOXYTETRANUCLEOTIDE 5"-d(ApCpGpT)

A. N. Veselkov, L. N. Djimant, P. A. Bolotin, S. F. Baranovsky, D. Davies

Temperature dependences of the chemical shifts of non-exchangeable ethidium bromide protons in a mixture with the deoxytetranucleoside triphosphate 5'-d(ApCpGpT) in aqu¬eous solution have been investigated with a pulsed n. m. r. spectrometer (500 MHz). Original methods of calculation of thermodynamic parameters of complexing, which gives an opportunity to get individual contributions of each reaction leading to the formation of 1:1, 1:2, 2:1 and 2:2 complexes of dye and tetranucleotide molecules in conditions of the composite equilibrium in solution, have been used. The free Qibbs energies, enthalpies and entropies of these reactions have been determined.