Xu Li,Yue Yuan,Yuting Wang,Fengming Zhang,Rui Zhao,Di Shao,Shuyun Bi
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 × 10 3 , 6.21 × 10 3 and 5.61 × 10 3 M −1 at 291, 301 and 311 K respectively and the binding distance r 0 was 5.30 nm. Thermodynamic parameters, such as Δ H Ө =−7.90 kJ mol −1 and Δ S Ө = 46.39 J mol −1 K −1 , showed that electrostatic attraction was the key force in the binding.
Rui Wang,Xing Hu,Junhui Pan,Guowen Zhang,Deming Gong
Isoeugenol , a natural phenolic compound in plant essential oils, is known to have many biological and pharmacological properties . In the present work, the interaction of isoeugenol with calf thymus DNA (ctDNA) and its protective effect on DNA oxidative damage were investigated by multispectroscopic techniques, viscosity measurements, gel electrophoresis studies and molecular simulation. Analyses of ultraviolet-visible (UV–vis) absorption and fluorescence spectra indicated that isoeugenol could bind to ctDNA with a binding constant on the order of 10 3 L mol −1 , which was mainly driven by hydrogen bonding and van der Waals forces . The results from the viscosity measurements, competitive displacement studies and circular dichroism (CD) analysis indicated that the binding of isoeugenol to ctDNA was in the groove mode and that the A–T base pairs in the minor grooves of ctDNA were the main binding sites for isoeugenol, which was supported by molecular docking analyses. In addition, isoeugenol was found to show a protective effect against hydroxyl-induced DNA damage, which may be explained by its good antioxidant activity . These findings may improve the understanding of the mechanism of interaction between isoeugenol and ctDNA and provide a theoretical basis for the development of isoeugenol in the food and drug industry.
Rui Wang,Na Li,Xing Hu,Junhui Pan,Guowen Zhang,Xinan Zeng,Deming Gong
The binding characteristics of food antioxidant tert -butylhydroquinone (TBHQ) and its oxidation product tert -butylquinone (TBQ) with calf thymus DNA (ctDNA) in vitro were investigated using multispectroscopy, chemometrics , viscosity measurements, gel electrophoresis assays and molecular docking . Analysis of fluorescence spectra found that TBHQ and TBQ bound with ctDNA to form 1:1 complexes with the binding constant in the order of 10 4 L mol −1 . The concentration profiles and the pure spectra for the components (TBHQ, TBQ, ctDNA and TBHQ– or TBQ–ctDNA complex) were obtained through analyzing the expanded ultraviolet-visible absorption data matrix by multivariate curve resolution–alternating least squares algorithm, which successfully monitored the binding process of TBHQ/TBQ with ctDNA. Fluorescence displacement, viscosity and molecular docking experiments showed that TBHQ bound to ctDNA through intercalation binding, while TBQ bound to the minor groove of ctDNA. The binding of TBHQ to ctDNA induced the conversion of DNA conformation from B-form to A-form, while TBQ caused a minor perturbation on the DNA conformation. Gel electrophoresis results indicated that the combination of TBHQ and Cu(II) could induce DNA damage. This study may contribute to understanding the binding mechanisms of TBHQ and TBQ with ctDNA and further evaluate the potential toxicological effects of TBHQ as a food additive .
危险品化学品经营许可证（带存储）