Background: Controlling the structure of proto-oncogene telomeres is very important in antitumor therapy. There are relationships between G-quadruplex DNA and the growth of tumor cell.

Methods: In this study, spectroscopic, cyclic voltammetry and viscosity methods were employed to investigate the interaction between Zn-Arsenazo Ⅲ complex and G-quadruplex DNA by using 4S Green Plus Nucleic Acid Stain as a spectral probe in PBS buffer. The binding ratios were n Arsenazo Ⅲ : n Zn(Ⅱ) = 5:1 for Zn-Arsenazo Ⅲ complex and n Zn- Arsenazo Ⅲ : n G-quadruplex DNA = 8:1 for Zn-Arsenazo Ⅲ-G-quadruplex DNA. The bonding constants (Kθ _298.15K=4.44x10⁵ L·mol^-1, Kθ _308.15K= 1.00x10⁵ L·mol^-1, Kθ _318.15K= 1.04x10⁶ L·mol^-1) were obtained by double reciprocal method at different temperatures, Which was found that the interaction between Zn-Arsenazo Ⅲ complex and Gquadruplex DNA was driven by enthalpy. Furthermore, the research further confirmed that the interaction mode between Zn-Arsenazo Ⅲ complex and G-quadruplex DNA was a mixed binding which involved intercalation and non-intercalation interaction.

Results and Conclusion: Together these findings also have corroborated the application of stabilizing ligands and intervening with their function for target G-quadruplexes in a cellular context.

背景：控制原癌基因端粒的结构在抗肿瘤治疗中非常重要。G-四链体DNA与肿瘤细胞的生长之间存在联系。

方法：采用光谱，循环伏安法和粘度法，以PBS缓冲液中的4S Green Plus核酸染色剂为探针，研究Zn-ArsenazoⅢ配合物与G-quadruplex DNA之间的相互作用。Zn-ArsenazoⅢ复合物的结合比为n ArsenazoⅢ：n Zn（Ⅱ）= 5：1，而Zn-ArsenazoⅢ-G-quadruplexDNA的n Zn- ArsenazoⅢ：n G-quadruplex DNA = 8：1。接合常数（Kθ _298.15K = 4.44x10 ⁵ L·摩尔^-1，Kθ _308.15K = 1.00×10 ⁵ L·摩尔^-1，Kθ _318.15K = 1.04x10 ⁶ L·摩尔^-1）是在不同温度下通过双向倒数法获得的，结果发现Zn-ArsenazoⅢ复合物与Gquadruplex DNA之间的相互作用是由焓驱动的。此外，研究进一步证实Zn-ArsenazoⅢ复合物与G-四链体DNA之间的相互作用方式是混合结合，涉及嵌入和非嵌入相互作用。

结果与结论：这些发现共同也证实了稳定配体的应用及其在细胞环境中对靶G-四链体的功能干预。