光谱法研究有机农药污染物与DNA的相互作用

利用紫外光谱、荧光光谱及圆二色谱(CD)等光谱方法研究了有机农药敌敌畏(DDVP)、乐果(DIM)、氧化乐果(OME)及生物农药申嗪霉素的有效成分吩嗪-1-羧酸(PCA)与端粒脱氧核糖核酸(DNA)间的相互作用。 结果表明，有机农药分子可能主要以嵌入模式与DNA结合，DDVP、DIM、OME以及PCA与端粒DNA之间的表观结合常数分别为：1.17×106、1.48×106、4.52×105和1.80×106 L/mol,与DNA结合能力的大小顺序为PCA＞DIM＞DDVP＞OME。 这些有机农药分子明显不利于DNA双螺旋结构的稳定性。 有机农药分子的嵌入削弱了DNA碱基对之间的π-π堆积作用，对DNA的二级结构有一定的影响,使得DNA的双螺旋结构变得松散。

Spectrometric Study on the Interactions Between Organic Pesticide Pollutants and DNA

The interactions of organic pesticide pollutants including, dichlorvos(DDVP), omethoate(OME), dimethoate(DIM) and plenazine-1-carboxylic acid(PCA), with the telomere DNA were investigated with ultraviolet spectroscopy, fluorescence spectroscopy and circular dichroism(CD). The results indicated that the organic pesticide pollutants interact with DNA mainly through the intercalative mode. The apparent binding constants of organic pesticides with DNA were calculated to be 1.17×106, 1.48×106, 4.52×105, and 1.80×106 L/mol, respectively. The apparent binding constants revealed that the order of the relative binding affinity is PCA＞DIM＞DDVP＞OME. The CD measurement indicated that these organic pesticide pollutants caused instability of the structure of the duplex DNA by weakening the π-π stacking of DNA base pairs. To some extent, it also affected the secondary structure of DNA, leading to the relaxing of the twin helix structure.