Deciphering the groove binding modes of tau-fluvalinate and flumethrin with calf thymus DNA.
Deciphering the groove binding modes of tau-fluvalinate and flumethrin with calf thymus DNA.
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DOI：
10.1016/j.saa.2015.11.006
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发表时间：
2016-02
期刊：
影响因子：
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通讯作者：
Mo Tao;Guowen Zhang;Jun-hui Pan;Chunhong Xiong
中科院分区：
文献类型：
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作者：
Mo Tao;Guowen Zhang;Jun-hui Pan;Chunhong Xiong
氟胺氰菊酯（TFL）和氟菊酯（FL）是一类结构相似的拟除虫菊酯类农药，在农业上广泛使用，存在潜在的安全风险。本文采用荧光光谱、紫外-可见吸收光谱、圆二色谱（CD）和傅里叶变换红外光谱（FT-IR）等方法，结合粘度测量、熔融分析和分子对接研究，对TFL和FL与小牛胸腺DNA（ctDNA）的体外结合模式进行了表征。荧光滴定表明TFL和FL均通过氢键和货车范德华力与ctDNA形成复合物。TFL和FL与ctDNA的结合常数在104 L mol− 1范围内，FL表现出比TFL更高的结合倾向。碘离子猝灭效应、单链/双链DNA效应、ctDNA熔解和粘度测定结果表明，TFL和FL与ctDNA的结合均为沟槽模式。FT-IR分析表明，TFL和FL优先结合于ctDNA小沟的A-T区，Hoechst 33258探针置换实验证实了这一点，分子对接显示了特异性结合。CD谱的变化表明，FL和TFL均对B-DNA的碱基堆积和螺旋度产生扰动，但FL的扰动更明显。凝胶电泳分析表明，TFL和FL都没有引起明显的DNA切割。本研究为TFL/FL与ctDNA的结合特性及其毒性机制提供了新的见解。
Tau-fluvalinate (TFL) and flumethrin (FL), widely used in agriculture and a class of synthetic pyrethroid pesticides with a similar structure, may cause a potential security risk. Herein, the modes of binding in vitro of TFL and FL with calf thymus DNA (ctDNA) were characterized by fluorescence, UV–vis absorption, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy with the aid of viscosity measurements, melting analyses and molecular docking studies. The fluorescence titration indicated that both TFL and FL bound to ctDNA forming complexes through hydrogen bonding and van der Waals forces. The binding constants of TFL and FL with ctDNA were in the range of 104L mol− 1, and FL exhibited a higher binding propensity than TFL. The iodide quenching effect, single/double-stranded DNA effects, and ctDNA melting and viscosity measurements demonstrated that the binding of both TFL and FL to ctDNA was groove mode. The FT-IR analyses suggested the A–T region of the minor groove of ctDNA as the preferential binding for TFL and FL, which was confirmed by the displacement assays with Hoechst 33258 probe, and the molecular docking visualized the specific binding. The changes in CD spectra indicated that both FL and TFL induced the perturbation on the base stacking and helicity of B-DNA, but the disturbance caused by FL was more obvious. Gel electrophoresis analyses indicated that both TFL and FL did not cause significant DNA cleavage. This study provides novel insights into the binding properties of TFL/FL with ctDNA and its toxic mechanisms.