Calorimetric and Spectroscopic Studies of Hoechst 33258: Self-association and Binding to Non-cognate DNA

Binding of streptomycin with bovine serum albumin: Energetics and conformational aspects

“…Though the interactions of some antibiotics with the serum albumin are reported in literature [11,[17][18][19], quantitative studies on the interaction of streptomycin with serum albumin addressing the energetics and type of interactions is not available in literature. A combination of isothermal titration calorimetry and fluorescence spectroscopy has yielded valuable information on binding interactions in biologically important systems both quantitatively and qualitatively [20][21][22][23][24][25]. In this work, we have used isothermal titration calorimetry in determining binding affinity, enthalpy, entropy and stoichometry …”

Homo‐ and Heteroleptic Phototoxic Dinuclear Metallo‐Intercalators Based on RuII(dppn) Intercalating Moieties: Synthesis, Optical, and Biological Studies

“…Typical enthalpograms for these titrations are shown in the SI. Potential binding models were explored by fitting a model involving two different DNA-ligand binding events to the calorimetric data using the I2CITC software package [38,39] , the data were reanalysed in terms of a model involving one binding site. The resulting thermodynamic parameters as summarized in Table 3 shows that the high affinity binding modes of complexes are very similar in binding site and affinity.…”

Dimerization Energetics of DNA Minor Groove Binders

“…Nevertheless, the obtained energies can be estimated quite adequately. In the literature, there are the experimental values concerning the total Gibbs energy Δ exp only for the dimerization of four-ring MGB ligands AIK-18/51 (an analog of TZA) [9] and Hoechst33258 [8]; they are equal to −6.0 and −5.0 kcal/mol, respectively. A typical calculation error for the total Gibbs energy of DNA-binding ligands has an order of magnitude of the energy itself [18,33], because each contribution to Δ total in Eq.…”

“…It was considered till now that a dimer of MGB ligands is formed directly on DNA by the consecutive binding of single ligand molecules with the latter. However, it was shown recently that a dimer can be formed irrespective of DNA in a free solution, and this newly formed dimer gets bound afterward with the biopolymer minor groove [7][8][9]. There are reasons to believe that such an "algorithm" of complex formation is entropically more beneficial than a consecutive molecule-by-molecule binding of single molecules.…”

“…In this connection, there emerges a problem, which has not been considered for MGB ligands till now, namely, the establishment of main regularities in the MGB-ligand dimerization in aqueous solutions and the revealing of physical factors that stabilize those ligands. In some earlier works (see, e.g., works [8,9]), only general thermodynamic parameters of dimerization were experimentally measured for MGB ligands Hoechst33258 and AIK-18/51; in particular, these are the variations of the Gibbs energy, Δ , enthalpy, Δ , entropy, Δ , and heat capacity, Δ . However the issue concerning the physical factors that stabilize MGB dimers has not been raised till now.…”