Binding mode and thermodynamic studies on the interaction of the anticancer drug dacarbazine and dacarbazine–Cu(II) complex with single and double stranded DNA

• We examined the interaction of anticancer Dac with ssDNA and dsDNA.
• The interaction of Dac with dsDNA indicated its intercalation.
• The binding mode of Dac with ssDNA is electrostatic attraction.
• Dac–Cu complex to DNA indicated a stronger intercalation than Dac.
• Dac–DNA at different temperatures leads to change in the thermodynamic stability of DNA.

The binding mode and thermodynamic characteristics of the anticancer drug dacarbazine (Dac) with double and single stranded DNA were investigated in the absence and presence of Cu(II) using cyclic voltammetry, square wave voltammetry and fluorescence spectroscopy. The interaction of Dac and Dac–Cu(II) complex with dsDNA indicated their intercalation into the base stacking domain of dsDNA double helix and the strength of interaction is independent on the ionic strength. The interaction of Dac with dsDNA in the presence of Cu(II) leads to a much stronger intercalation. The interaction mode of Dac molecules with ssDNA is electrostatic attraction via negative phosphate on the exterior of the ssDNA with Dac. The binding constants, stoichiometric coefficients and thermodynamic parameters of Dac and Dac–Cu(II) complex with dsDNA and ssDNA were evaluated. Comparison of the mode interaction of Dac with dsDNA and ssDNA was discussed. The decrease of peak current of Dac was proportional to DNA concentration, which was applied for determination of dsDNA and ssDNA concentration.

The binding mode and thermodynamic characteristics of the anticancer drug dacarbazine (Dac) with double stranded DNA were investigated using cyclic voltammetry. The interaction of Dac with dsDNA indicated its intercalation into the base stacking domain of dsDNA double helix. The formed anticancer Dac–DNA adduct at different temperatures leads to change in the thermodynamic stability and structural properties of DNA.Figure optionsDownload as PowerPoint slide