通过原位紫外和圆二色薄层光谱电化学研究DNA在电还原过程中的构象转变。

Conformational transition of DNA in electroreduction studied by in situ UV and CD thin layer spectroelectrochemistry.

作者信息

Zhu Y, Cheng G, Dong S

机构信息

Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, PR China.

出版信息

Biophys Chem. 2000 Oct 30;87(2-3):103-10. doi: 10.1016/s0301-4622(00)00170-8.

DOI:10.1016/s0301-4622(00)00170-8

PMID:11099173

Abstract

Electrochemically induced three conformational transitions of calf thymus DNA from B10.4 to Z10.2-DNA and from B10.2 to B10.4 and to C-DNA in 10 mM phosphate buffer solution (pH 7.21) at glassy carbon electrode are found and studied by in situ circular dichroism (CD) thin layer spectroelectrochemistry with singular value decomposition least square (SVDLS) analysis. It indicates that the so-called B10.2 form and the C-form of DNA may be composed of B10.4 and left-A DNA and of B10.4 and right-A DNA, respectively. The irreversible electrochemical reduction of adenine and cytosine groups in the DNA molecule is studied by UV-Vis spectroelectrochemistry. Some electrochemical parameters alpha n = 0.17, E0' = -0.70 V (vs. Ag/AgCl), and the standard heterogeneous electron transfer rate constant, k0 = 1.8 x 10(-5) cm s(-1), are obtained by double logarithmic analysis and non-linear regression.

摘要

在玻碳电极上，于10 mM磷酸盐缓冲溶液（pH 7.21）中，通过原位圆二色（CD）薄层光谱电化学结合奇异值分解最小二乘法（SVDLS）分析，发现并研究了小牛胸腺DNA的三种电化学诱导构象转变，即从B10.4转变为Z10.2 - DNA，以及从B10.2转变为B10.4和C - DNA。结果表明，所谓的DNA的B10.2形式和C形式可能分别由B10.4和左A - DNA以及B10.4和右A - DNA组成。通过紫外可见光谱电化学研究了DNA分子中腺嘌呤和胞嘧啶基团的不可逆电化学还原。通过双对数分析和非线性回归获得了一些电化学参数，αn = 0.17，E0' = -0.70 V（相对于Ag/AgCl），以及标准异相电子转移速率常数k0 = 1.8×10^(-5) cm s^(-1)。