DNA groove binding of an asymmetric cationic porphyrin and its Cu(II) complex: Resolved by spectroscopic, viscometric and molecular docking studies

In the present study, the interaction between watersoluble cationic asymmetric porphyrin, 5(1Hexadecyl pyridinium4yl)10, 15, 20tris (1Butyl pyridinium4yl) Porphyrin Chloride, and its copper (II) derivative with calf thymus DNA (CTDNA) were studied by means of spectroscopic techniques, viscosity measurements and molecular docking. The monitoring of the changes in visible absorbance spectra showed a small red shift and a little hypochromicity in the Soret band. Also, insignificant changes were appeared in the viscosity of DNA with increasing of the porphyrins. These results suggested that these porphyrins bound to DNA through the groove binding mode. Then, multivariate curve resolutionalternating least squares (MCRALS) method was employed on UV–visible spectral data matrix to resolve the spectral and concentration profiles of the components involved in the interaction and the binding constant was estimated by the combination of bard equation and MCRALS approach. Furthermore, molecular docking studies confirmed experimental results obtained by spectral techniques and provide deeper insight into the porphyrinDNA interaction.