Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Donghuan Road 268, Liuzhou 545006, Guangxi, PR China.
Guangxi Key Laboratory of Green Processing of Sugar Resources, Guangxi University of Science and Technology, Donghuan Road 268, Liuzhou 545006, Guangxi, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2020 Apr 5;230:118054. doi: 10.1016/j.saa.2020.118054. Epub 2020 Jan 10.
In this paper, the binding characteristics of aflatoxin B (AFB) with the herring sperm deoxyribonucleic acid (DNA) in vitro were investigated through different analytical methods. The ultraviolet-visible spectroscopy (UV-vis), fluorescence, and circular dichroism (CD) spectra results showed that a new AFB-DNA complex was formed. All the results suggested that AFB interacted with free DNA in vitro in an intercalating binding mode. The results of the DNA melting experiments also showed that the melting temperature of DNA increased by about 12.1 °C due to the addition of AFB, which was supposed to be closely related to the intercalation of AFB into DNA. The agar gel electrophoresis experiments further confirmed that the binding mode of AFB and free DNA in vitro was indeed intercalation. In addition, the fluorescence quenching induced by adding AFB to the ethidium bromide-DNA (EB-DNA) mixture indicated the presence of competitive non-covalent intercalating binding interaction with a competitive binding constant of 5.58 L/mol between AFB, EB, and DNA. The thermodynamic data demonstrated that the main driving forces of the binding reaction were van der Waals forces and hydrogen bond. The resonance light scattering (RLS) assay results showed that the DNA binding saturation values of AFB, EB, psoralen (PSO), and angelicin (ANG) were 2.14, 15.59, 0.74, and 0.74, respectively. These results indicated that the DNA binding capacity of AFB was weaker than that of EB, but stronger than those of PSO and ANG.
本文通过多种分析方法研究了黄曲霉毒素 B（AFB）与鲱鱼精 DNA 在体外的结合特性。紫外-可见光谱（UV-vis）、荧光和圆二色性（CD）光谱结果表明形成了新的 AFB-DNA 复合物。所有结果表明 AFB 以嵌入结合模式与游离 DNA 在体外相互作用。DNA 热融实验的结果也表明，由于加入 AFB，DNA 的熔点升高了约 12.1°C，这可能与 AFB 嵌入 DNA 密切相关。琼脂糖凝胶电泳实验进一步证实了 AFB 与游离 DNA 在体外的结合模式确实是嵌入。此外，向溴化乙锭-DNA（EB-DNA）混合物中加入 AFB 诱导的荧光猝灭表明存在与 EB、DNA 具有竞争性非共价嵌入结合相互作用的竞争结合常数为 5.58 L/mol。热力学数据表明，结合反应的主要驱动力是范德华力和氢键。共振光散射（RLS）测定结果表明，AFB、EB、补骨脂素（PSO）和花椒毒素（ANG）的 DNA 结合饱和值分别为 2.14、15.59、0.74 和 0.74。这些结果表明，AFB 的 DNA 结合能力弱于 EB，但强于 PSO 和 ANG。
