Abstract:

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.

Key words: Organic pesticide pollutants, Deoxyribonucleic acid, interaction, Intercalative mode