Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
J Agric Food Chem. 2010 May 12;58(9):5257-62. doi: 10.1021/jf1000748.
Terbium(III), as a good luminescent probe, was developed for the study of the interaction between paraquat and calf thymus DNA (ctDNA) when the binding mode of small molecules to DNA was electrostatic binding. This interaction was further investigated using an ethidium bromide (EB) probe, UV absorption spectra, and circular dichroism spectra. On the basis of Scatchard plots constructed from fluorescence titration data of the ctDNA-Tb(3+) system in the presence of paraquat, the binding constants between paraquat and ctDNA were obtained. The results showed that the electrostatic attraction between positively charged sodium ion and negatively charged phosphate groups could inhibit the binding of paraquat to ctDNA, and competitive inhibition between Tb(3+) and paraquat also existed when they were bound to ctDNA. The effects of paraquat on the fluorescence intensity of the EB-ctDNA system indicated that the intercalation binding of paraquat to ctDNA could be excluded. This conclusion could be further supported by both the absorption spectra of paraquat in the presence of ctDNA and the CD spectra of the paraquat-ctDNA system.
铽(III)作为一种良好的荧光探针，被开发用于研究百草枯与小牛胸腺 DNA（ctDNA）之间的相互作用，因为小分子与 DNA 的结合模式是静电结合。当小分子与 DNA 结合模式为静电结合时，该相互作用进一步使用溴化乙锭（EB）探针、紫外吸收光谱和圆二色光谱进行了研究。基于存在百草枯时 ctDNA-Tb(3+)体系荧光滴定数据构建的 Scatchard 图，获得了百草枯与 ctDNA 之间的结合常数。结果表明，带正电荷的钠离子与带负电荷的磷酸基团之间的静电吸引可以抑制百草枯与 ctDNA 的结合，并且当它们与 ctDNA 结合时，Tb(3+)和百草枯之间也存在竞争抑制。百草枯对 EB-ctDNA 体系荧光强度的影响表明，百草枯与 ctDNA 的嵌入结合可以被排除。这一结论可以通过 ctDNA 存在时百草枯的吸收光谱和百草枯-ctDNA 体系的 CD 光谱进一步得到支持。
Zotero 插件