Binding interaction of phatinaceutical drug captopril with calf thymus DNA: a multispectroscopic and molecular docking study

Exploring the binding interaction of drug molecule with calf thymus DNA turn out to be a dynamic field of research at the interface between biological science and medicinal chemistry. Captopril, an angiotensin-converting enzyme inhibitor and extensively used for the treatment of hypertension and cognitive heart failure. Still now, its interaction style with ctDNA is not well interpreted. In this issue, we have tried to find out the binding mode of captopril with ctDNA under physiological pH using fluorescence probe pyrene by spectroscopic methods along with molecular docking study. UV-vis absorption, emission and time-resolved fluorescence spectroscopy suggest the non-covalent binding interaction between captopril and ctDNA with binding constant value 5.47 x 10(3) M-1. The circular dichroism measurement reveals the conformational change of ctDNA upon addition of captopril. Binding nature of captopril with ctDNA is affirmed from the Isothermal Titration Calorimetry, helix melting experiment, comparative displacement assay, cyclic voltammetry, viscometric study and finally molecular docking. Thermodynamic parameters Delta H, Delta S and Delta G transpired that captopril probably binds to minor groove of ctDNA. The groove binding nature of captopril with ctDNA was confirmed by molecular docking study. Hence, the results gained from current inspection give an explicit visualization of the effects of captopril with ctDNA interaction.