Theoretical and Instrumental Studies of the Competitive Interaction Between Aromatic α-Aminobisphosphonates with DNA Using Binding Probes

Fluorescence spectroscopy, UV–visible absorption spectroscopy, circular dichroism (CD) spectroscopy, viscometry, cyclic voltammetry (CV), and differential pulse voltammetry (DPV) were applied to investigate the competitive interaction of DNA with two aromatic α-aminobisphosphonates and neutral red dye (NR, intercalator) and Hoechst (Ho, groove binder) as spectroscopic probes, in a Tris–hydrogen chloride buffer solution (pH 7.4). The principal component analysis (PCA) was applied to determine the number of chemical components presented in complexation equilibrium of DNA with the aromatic α-aminobisphosphonates (B 1 and B 2 ). The spectroscopic and voltammetric studies showed that the groove binding mode of interaction is predominant in the solution containing DNA and α-aminobisphosphonates. Furthermore, the results indicated that α-aminobisphosphonate with the lengthy N -alkyl chains had a stronger interaction. The PCA and theoretical quantum mechanical and molecular mechanic methods were also utilized to determine the structure of DNA with the two α-aminobisphosphonates (B 1 and B 2 ).