Binding elucidation of azo dye with DNA via spectroscopic approaches and molecular docking techniques

In this study, the interaction between a synthesized monoazo disperse dye and calf thymus DNA (Ct-DNA) was investigated via UV?Vis spectroscopy, fluorescence and FT-IR spectroscopy and molecular docking calculations. Hypochromic effects on the absorbance and quenching of fluorescence were observed, revealing the binding of azo dye to Ct-DNA. Upon the addition of Ct-DNA, the azo dye showed a hypochromic effect and a small redshift in the wavelength of the absorption spectra, suggesting a groove binding mode of interaction of this probe with Ct-DNA, which was confirmed by the molecular docking results. The values of the binding constant were calculated from the maximum absorption spectra of the azo dye at various Ct-DNA concentrations at several temperatures and the corresponding thermodynamic parameters ?G?, ?H? and ?S? were obtained. In addition, fluorescence resonance energy transfer showed that the distance between the donor (EB?Ct-DNA) and acceptor (azo dye) is suitable for energy transfer. Molecular docking analysis revealed that hydrogen bonds and ?-electrons on the benzene ring of the azo dye are crucial for binding the azo dye to Ct-DNA. The results of the molecular docking investigations corroborate well with those of the spectral studies and these probes bind to the minor groove of Ct-DNA.