Yildiz Technical University, Chemistry Department, Davutpasa Campus, 34220 Esenler, Istanbul, Turkey.
Yildiz Technical University, Chemistry Department, Davutpasa Campus, 34220 Esenler, Istanbul, Turkey.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Nov 5;204:281-286. doi: 10.1016/j.saa.2018.06.001. Epub 2018 Jun 2.
Thioxanthone and its derivatives are the most remarkable molecules due to their vast variety of application such as radiation curing that is, until using them as a therapeutic drug. Therefore, in this study it was intended to use 2-Thioxanthone acetic acid with and without NaCl in Tris HCl buffer solution (pH:7.0) to represent the interaction with ct-DNA. The UV-vis absorption spectra of TXCHCOOH in the presence of ct-DNA showed hypochromism and the intrinstic binding constant (K) was determined as 6 × 10 L mol. The fluoresence intensity of TXCHCOOH with ct-DNA clearly increased up to 101% which indicated that the fluorescence intensity was very sensitive to ct-DNA concentration. The binding constant (K) and the values of number of binding sites (n) and were calculated as 1.8 × 10 L mol and 0.69, respectively. When the quenching constants (K) of free TXCHCOOH and TXCHCOOH, which were bonded with ct-DNA were compared, slightly changed values of Ksv were seen. Moreover, displacement assay with Hoechst 33,258 and viscosity measurements in the presence and absence of NaCl salt also confirmed the binding mode which noted the electrostatic interaction following groove binding between TXCHCOOH and ct-DNA. Last but not least, the salt effect was examined on ct-DNA binding with TXCHCOOH. The results of the experiments indicated that the groove binding was strengthened by NaCl whereas in the high NaCl concentration, the binding ability of TXCHCOOH to ct-DNA was inversely affected.
硫杂蒽酮及其衍生物是最显著的分子，因为它们有各种各样的应用，如辐射固化，直到将它们用作治疗药物。因此，在这项研究中，我们意图使用 2-硫杂蒽酮乙酸及其与 NaCl 形成的混合物在 Tris HCl 缓冲溶液（pH：7.0）中，来代表与 ct-DNA 的相互作用。在存在 ct-DNA 的情况下，TXCHCOOH 的紫外可见吸收光谱表现出减色效应，并且确定了内在结合常数（K）为 6×10 L mol。TXCHCOOH 与 ct-DNA 的荧光强度明显增加了 101%，这表明荧光强度对 ct-DNA 浓度非常敏感。结合常数（K）和结合位点数量（n）的值分别计算为 1.8×10 L mol 和 0.69。当比较游离 TXCHCOOH 和与 ct-DNA 结合的 TXCHCOOH 的猝灭常数（K）时，观察到 Ksv 值略有变化。此外，使用 Hoechst 33,258 进行置换实验和在存在和不存在 NaCl 盐的情况下进行粘度测量也证实了结合模式，即 TXCHCOOH 与 ct-DNA 之间的静电相互作用遵循沟结合。最后但并非最不重要的是，检查了盐效应对 TXCHCOOH 与 ct-DNA 结合的影响。实验结果表明，NaCl 增强了沟结合，而在高 NaCl 浓度下，TXCHCOOH 与 ct-DNA 的结合能力受到相反的影响。
