DNA binding affinity of a macrocyclic copper(II) complex: Spectroscopic and molecular docking studies

ABSTRACTThe interaction of a novel macrocyclic copper(II) complex, ([CuL(ClO4)2] that L is 1,3,6,10,12,15-hexaazatricyclo[13.3.1.16,10]eicosane) with calf thymus DNA (ct-DNA) was investigated by various physicochemical techniques and molecular docking at simulated physiological conditions (pH = 7.4). The absorption spectra of the Cu(II) complex with ct-DNA showed a marked hyperchroism with 10 nm blue shift. The intrinsic binding constant (Kb) was determined as 1.25 × 104 M−1, which is more in keeping with the groove binding with DNA. Furthermore, competitive fluorimetric studies with Hoechst33258 have shown that Cu(II) complex exhibits the ability to displace the ct-DNA-bound Hoechst33258 indicating that it binds to ct-DNA in strong competition with Hoechst33258 for the groove binding. Also, no change in the relative viscosity of ct-DNA and fluorescence intensity of ct-DNA-MB complex in the present of Cu(II) complex is another evidence to groove binding. The thermodynamic parameters are calculated by van'...