物理化学学报 >> 2003, Vol. 19 >> Issue (11): 1064-1068.doi: 10.3866/PKU.WHXB20031116

研究论文 上一篇    下一篇

溶液pH对硫堇与DNA相互作用方式的影响

杜江燕;黄晓华;徐飞;邢巍;陆天虹   

  1. 中国科学院长春应用化学研究所,长春 130022; 南京师范大学化学与环境科学学院,南京 210097
  • 收稿日期:2003-05-13 修回日期:2003-07-25 发布日期:2003-11-15
  • 通讯作者: 陆天虹 E-mail:tianhonglu@263.net

Effect of pH on the Interaction Mode between TH and CT-DNA

Du Jiang-Yan;Huang Xiao-Hua;Xu Fei;Xing Wei;Lu Tian-Hong;   

  1. Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022; College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097
  • Received:2003-05-13 Revised:2003-07-25 Published:2003-11-15

摘要: 用电化学和光谱方法研究了溶液pH对硫堇(TH)与小牛胸腺脱氧核糖核酸(CT-DNA)相互作用方式的影响.电化学测量结果表明,在pH 7.2的磷酸盐缓冲溶液中, TH与CT-DNA之间的作用方式以嵌入结合为主,在pH 6.5的磷酸盐缓冲溶液中, TH与CT-DNA之间的作用方式既存在嵌入结合也存在静电作用.荧光光谱测量结果表明,TH与DNA结合后其荧光发生猝灭,通过Stern-Volmer方程计算得到pH 6.5时TH-DNA体系的猝灭常数高于pH 7.2时的值,表明在pH 6.5的溶液中两者相互作用更强.圆二色谱(CD)实验结果也证实了这一结论.

关键词: 硫堇, DNA, 电化学反应, 荧光光谱, 圆二色谱

Abstract: The effect of pH of solution on the interaction between TH(thionine) and CT-DNA was studied using electrochemical and spectroscopic methods. The electrochemical results indicated that the interaction between TH and CT-DNA is in the intercalative mode in the pH 7.2 phosphate buffer solution, but both intercalative and electrostatic modes exist in the pH 6.5 phosphate buffer solution. Fluorescence spectroscopic results showed that the fluorescence intensity of TH is efficiently quenched by CT-DNA bases. The quenching constant, KSV obtained from the Stern-Volmer equation for the pH 6.5 solution is larger than that for the pH 7.2 solution indicating that the interaction between TH and CT-DNA in the pH 6.5 solution is stronger than that in the pH 7.2 solution. The conclusion is confirmed by the results of CD spectroscopic measurements.

Key words: Thionine, DNA, Electrochemical reaction, Fluorescence spectrum,  Circular dichroism