Study of DNA interactions with bifenthrin by spectroscopic techniques and molecular modeling

The interaction between bifenthrin (BF) and calf thymus DNA (ctDNA) in physiological buffer (pH 7.4) was investigated by UV-vis absorption, fluorescence, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectroscopy, coupled with viscosity measurements and molecular docking techniques. It was found that BF molecular could intercalate into the base pairs of ctDNA as evidenced by significant increases in absorption intensity, fluorescence polarization and relative viscosity of ctDNA, decrease in iodide quenching effect, and induced CD spectral changes. The association constant of BF with ctDNA was evaluated to be in the order of 10(4) L mol(-1). Thermodynamic analysis of the binding data obtained at different temperatures suggested that the binding process was primarily driven by hydrogen bonds and van der Waals forces, as the values of the enthalpy change (ΔH) and the entropy change (ΔS) were calculated to be -31.13±1.89 kJ mol(-1) and -22.79±1.21 J mol(-1) K(-1), respectively. The results of FT-IR spectra and molecular docking showed that a specific binding mainly existed between BF and adenine and guanine bases.