钆(Ⅲ)-氧氟沙星配合物与DNA的相互作用

Interaction between Gd(Ⅲ)-ofloxacin coordination compound and DNA

目的:研究钆(Ⅲ)-氧氟沙星配合物与DNA的相互作用。方法:通过荧光光谱、黏度测定、溴化乙锭(EB)竞争实验、盐效应以及凝胶电泳实验研究钆(Ⅲ)-氧氟沙星配合物与DNA的相互作用。结果:DNA能使该配合物的荧光产生猝灭,其猝灭常数Ksv为5.21×104L/mol,猝灭机理为静态猝灭;同时,该配合物可使DNA的黏度降低,说明该配合物主要以部分嵌插的作用方式与DNA结合;另外通过溴化乙锭(EB)竞争实验进一步证实了配合物与DNA是以嵌插的作用方式相结合的;盐效应则说明配合物与DNA之间不存在静电引力;凝胶电泳实验表明该配合物能造成质粒DNA的断裂。结论:钆(Ⅲ)-氧氟沙星配合物与DNA相互作用的方式以嵌插方式为主,凝胶电泳实验的结果说明该配合物对DNA有切割作用,具有一定的生理活性。

Aim：To study the interaction between Gd （ Ⅲ ）-ofloxacin coordination compound and calf thymus DNA. Methods：The interaction was investigated by the fluorescent spectroscopy, viscosity titration, ethidium bromide （EB） competitive, ionic influence and gel electrophoresis. Results：The fluorescence of the Gd （ Ⅲ ）-ofloxacin coordination compound was decreased in the presence of DNA, and the static quenching constant （ Ksv ） was determined to be 5.21 × 10^4 L/mol. The mechanism of static quenching was confirmed. The coordination compound decreased the viscosity of calf thymus DNA, which could be explained by the partial intercalation as the main interaction between the coordination compound and DNA. In addition EB competition study also showed the coordination compound interacted with DNA mainly by intercalation. Furthermore, ionic influence experiment demonstrated that there was no electrostatic interaction between the coordination compound and DNA. Gel electrophoresis showed the coordination compound also was responsible for single strand cleavage in plasmid DNA. Conclusion： The manner of the interaction between Gd （ Ⅲ ）- ofloxacin coordination compound and DNA was uncovered in a certain extent. The results from gel electrophoresis demonstrated the physiological activity of the coordination compound.