Study on the Mechanism of DNA Conformation Change Induced by Cr(Ⅵ)-GSH Complex / 环境与健康杂志

ABSTRACT

Objective To study the interaction between Cr(Ⅵ)-GSH complex and DNA and to understand the mechanism of DNA conformation change induced by Cr(Ⅵ)-GSH complex. Methods Chromium(Ⅵ) reacts on glutathione forms the chromium (Ⅴ) intermediate complex, and the intermediate complex can induce the conformation change of DNA, in the present paper, ultraviolet and fluorescence spectra, Scatchard equation, fluorescence quenching curve, and fluorescence probe method using ethidium bromide (EB) as a fluorescence probe were employed. Results The chromium (Ⅴ) intermediate complex formed rapidly after the reaction between Cr(Ⅵ) and GSH in Hepes buffer solution at pH=7.4, the complex did not insert into the base pairs on the DNA duplex strand and developed electrostatic binding with the phosphate backbone of DNA, but induced a conformation change of DNA leading to a disruption of duplex structure. In the following time, the complex decomposed and the end product was Cr(Ⅲ), Cr(Ⅲ) can cross-link with DNA, the whole process needs about an hour. Conclusion The chromium(Ⅴ) intermediate complex of the conformation change reaction of chromium(Ⅵ) and glutathione may play an important role in inducing the DNA.