Ca^(2+)、Mg^(2+)对农药三唑醇与小牛胸腺DNA相互作用的影响

Effect of Ca^(2+) and Mg^(2+) on Interaction between Triadimenol and Calf Thymus DNA

在pH 7.4的Tris-HCl缓冲溶液中,以溴化乙锭(EB)荧光探针,采用荧光和紫外-可见光谱法并结合DNA熔点测量和黏度实验,研究了Ca2+、Mg2+分别对农药三唑醇与小牛胸腺DNA(ctDNA)结合模式的影响。结果表明:三唑醇主要以嵌插模式与ctDNA结合,Ca2+、Mg2+的存在均能增强三唑醇与ctDNA的相互作用,随着体系中Ca2+、Mg2+浓度的增加,ctDNA-三唑醇复合物的结合常数均呈现出先增大后减小的趋势,表明Ca2+、Mg2+对ctDNA-三唑醇结合的影响取决于金属离子与DNA的碱基和磷酸基团之间的结合程度。

The effect of Ca2＋ and Mg2＋ on the binding interaction of triadimenol with calf thymus DNA（ctDNA） was studied with ethidium bromide（EB） as a flurescence probe using fluorescence and UV-vis absorption spectroscopy combined with DNA melting measurements and viscosity experiments.The results showed that triadimenol could bind to ctDNA through intercalation mode.Both of the two metal ions could affect the absorption spectra of triadimenol and enhance the interaction between ctDNA and triadimenol.The binding constants of ctDNA-triadimenol complex tended to increase initially and then decrease with the increasing concentration of the two metal ions.It can be deduced that the effect of metal ions on the binding between triadimenol and DNA mainly depends on the relative affinity between metal ions and triadimenol,DNA basic groups or phosphate groups.