Binding study of florfenicol with DNA by multi-spectroscopy and molecular docking techniques

Abstract

The investigation on the binding interaction mechanism of florfenicol with DNA in vitro was reported via multi-spectroscopy measurements and molecular docking approach in the present work. The static fluorescence quenching process accompanied with non-radiation energy transfer between florfenicol and DNA was confirmed by Stern-Volmer analysis, lifetime measurement and fluorescence resonance energy transfer study. Florfenicol was the A-T rich minor groove binding agent of DNA. Various experiments including site marker competitive experiments, viscosity measurements, helix melting studies, ionic strength measurements, thermal denaturation experiments, circular dichroism (CD) spectra measurements and UV–vis spectra characteristics were carried out to disclose the interaction mode. In addition, molecular docking stimulated appropriate binding orientation to further prove above experimental results. The binding constants were 6.92 × 103, 6.21 × 103 and 5.61 × 103 M−1 at 291, 301 and 311 K respectively and the binding distance r0 was 5.30 nm. Thermodynamic parameters, such as ΔHӨ =−7.90 kJ mol−1 and ΔSӨ = 46.39 J mol−1 K−1, showed that electrostatic attraction was the key force in the binding.