Competitive displacement assays further confirmed a non-intercalative binding mode of 6MP which was further confirmed by CD and viscosity experiments. Steady state fluorescence experiments revealed a moderate binding constant of 7.48×10 3 M −1 which was consistent with an external binding mode. UV-visible spectroscopy confirmed 6MP-DNA interaction. Interaction of an antimetabolite anticancer drug 6mercaptopurine (6MP) with calf thymus DNA was studied using various approaches like UV-visible spectroscopy, fluorescence spectroscopy, CD, viscosity and molecular docking. The ability of small molecules to bind and interfere with DNA replication and transcription provides further insight into how the drugs control the expression of genes.
Elucidating the binding between small molecules and DNA provides great help in understanding drug-DNA interactions and in designing of new and promising drugs for clinical use. DNA is one of the major intracellular targets for a wide range of anticancer and antibiotic drugs.
