Interaction of procarbazine with calf thymus DNA-a biophysical and molecular docking study

Interaction of procarbazine (PCZ) with calf thymus DNA was studied using biophysical and molecular docking studies. Procarbazine was to interact with DNA with a binding constant of 6.52 × 10³  M^-1 as calculated using ultraviolet-visible spectroscopy. To find out the binding mode, molecular docking was performed that predicted PCZ to interact with DNA through groove binding mode with binding affinity of -6.7 kcal/mole. To confirm the groove binding nature, different experiments were performed. Dye displacement assays confirmed the non-intercalative binding mode. Procarbazine displaced Hoechst dye from the minor groove of DNA while it was unable to displace intercalating dyes. There was no increase in the viscosity of DNA solution in presence of PCZ. Also, negligible change in the secondary structure of DNA was observed in presence of PCZ as evident by circular dichroism spectra. Procarbazine caused decrease in the melting temperature of DNA possibly because of decrease in the stability of DNA caused by groove binding interaction of PCZ with DNA.