Analysis of Calorimetric Data for Binding of Monomeric Bisbenzimidazole, an Analogue of the Dye Hoechst 33258, to Рory(dA)•Рory(dT)
The enthalpy and entropy of the monomeric bisbenzimidazole, an analogue of the dye Hoechst 33258, binding was evaluated based on the analysis of calorimetric data for reverse titration of this ligand with poly(dA)-poly(dT). A mathematical model enabling measurement of thermodynamic parameters of binding with calorimetric data was described. The results obtained were in a good agreement with data for binding of analogous compounds identified spectrophotometrically. Binding parameters of dimeric bisbenzimidazole composed of two monomeric bisbenzimidazole molecules linked via flexib1e chain were evaluated using this model. A conclusion was made that there exist different types of the complex between this ligand and a polymer.