Du Jiang-yan, Huang Xiao-hua, Xu Fei, Feng Yu-ying, Xing Wei, Lu Tian-hong
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2005 Sep;25(9):1435-8.
The interaction mechanism of thionine (TH) and calf thymus DNA (CT-DNA) was studied with UV-Vis absorption spectoscopy, fluorescence spectroscopy, circular dichroism (CD), and X-ray photoelectron spectroscopy (XPS). It was demonstrated that in the pH 7.2 phosphate buffer solution, the interaction of TH and CT-DNA is in the intercalative mode. The absorbance of the absorption peak of TH decreases and the peak position shifts to the red direction. The binding constant (K) of TH with CT-DNA is 1.45x 10(4) mol x L(-1). The fluorescence intensities of TH decrease drastically with increasing the concentration of CT-DNA. The Stem-Volmer quenching constant (Ksv) was calculated to be 1.01 x 10(4) mol x L(-1). The intercalative sites are mainly located at the G-C sequences of the CT-DNA molecule through the S atom in the TH molecule according to the experimental data obtained from the fluorescence spectra and XPS analysis. The secondary structure conformation of CT-DNA is changed due to its interaction with TH.
采用紫外可见吸收光谱、荧光光谱、圆二色光谱（CD）和X射线光电子能谱（XPS）研究了硫堇（TH）与小牛胸腺DNA（CT-DNA）的相互作用机制。结果表明，在pH 7.2的磷酸盐缓冲溶液中，TH与CT-DNA的相互作用为嵌入模式。TH吸收峰的吸光度降低，峰位向红移。TH与CT-DNA的结合常数（K）为1.45×10⁴ mol·L⁻¹。随着CT-DNA浓度的增加，TH的荧光强度急剧下降。计算得到的斯特恩-沃尔默猝灭常数（Ksv）为1.01×10⁴ mol·L⁻¹。根据荧光光谱和XPS分析获得的实验数据，嵌入位点主要通过TH分子中的S原子位于CT-DNA分子的G-C序列处。CT-DNA的二级结构构象因其与TH的相互作用而发生改变。
