荧光光谱法研究对-二甲氨甲基-杯[8]芳烃与DNA相互作用

首次采用阿霉素作荧光探针研究了水溶性对-二甲氨甲基-杯8]芳烃(简称杯8]胺或CX8)与小牛胸腺DNA相互作用,并考察了溶液的pH值、离子强度及解链DNA对DNA和杯8]胺相互作用的影响。实验发现,DNA能猝灭阿霉素的荧光,向该体系中加入杯8]胺时荧光又逐渐增强,这说明杯8]胺能与DNA的磷氧负离子强烈作用。通过Scatchard图等进一步分析发现,杯8]胺对DNA-阿霉素的影响表现为混合模式,一方面,在中性或酸性的条件下,杯8]胺能中和DNA上的磷氧负离子,导致DNA收缩,从而影响DNA的构象,使嵌入的阿霉素从DNA中部分游离出来,荧光增强;另一方面,杯8]胺与阿霉素也存在静电位点竞争。

Study on the Interaction of Water-Soluble p-(N, N-Dimethylaminomethyl)calix[8]arene with DNA by Fluorescent Spectrometry

The interaction of water-soluble p-(N, N-dimethylaminomethyl)calix8]arene (CX8) with DNA was studied using (adriamycin)(ADM) as a probe by fluorescent spectrometry. The effect factors such as, pH of solution, salt effect and unlinking DNA on the spectra were also investigated. The interaction mechanism was proposed. The authors observed that the fluorescence of ADM was quenched by calf thymus DNA, and the fluorescence intensity of DNA-ADM enhanced with the increasing of the CX8 gradually. The result (indicates) that the strong electrostatic interaction between the oxyphosphate anion of DNA and the CX8 existed. According to the plot of scatchard, the results imply that the influence of CX8 on interaction of DNA-ADM belongs to mixed model, on the one hand, in the condition of neutral and acidity, the oxyphosphate anion of DNA can be neutralized by CX8 partially, which induced the contraction of DNA and the conformational change of DNA, which led to release ADM from DNA partially, on the other hand, the CX8 can also compete the electrostatic sites with ADM directly.