Binding of an indole alkaloid, vinblastine to double stranded DNA: A spectroscopic insight in to nature and strength of interaction

Vinblastine is a chemotherapeutic drug, used for the treatment of various cancers. It functions by interfering with DNA in fast growing cells and preventing them from reproducing. The present work is focused on the interaction of vinblastine with double stranded DNA in aqueous solution. Fourier transform infrared and UV-Visible absorption spectroscopy were used to analyze the interaction of vinblastine with calf-thymus DNA. FTIR analysis showed binding of vinblastine through A-T and G-C base pairs of DNA along with its phosphate backbone. UV-Vis spectroscopy results suggested the intercalation of drug in between the base pairs of DNA double helix. The binding constant estimated for vinblastine-DNA association was found to be K = 1.7 x 10(3) M-1. Molecular docking was performed and the results showed adenine base binding of vinblastine with DNA. Furthermore spectroscopic results revealed that formation of vinblastine-DNA complex resulted in no major change in the B-conformation of DNA