Probing mercury species-DNA interactions by capillary electrophoresis with on-line electrothermal atomic absorption spectrometric detection
Probing mercury species-DNA interactions by capillary electrophoresis with on-line electrothermal atomic absorption spectrometric detection
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DOI：
10.1021/ac060644a
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发表时间：
2006-09-01
影响因子：
7.4
通讯作者：
Yan, Xiu-Ping
中科院分区：
文献类型：
--
作者：
Li, Yan;Jiang, Yan;Yan, Xiu-Ping
采用毛细管电泳-在线火焰原子吸收光谱法（CE-ETAAS）结合圆二色谱和傅里叶变换红外光谱研究了无机汞Hg（II）、甲基汞（MeHg（I））、乙基汞（EtHg（I））和苯基汞（PhHg（I））与DNA的相互作用。CE-ETAAS分析允许灵敏地探测汞物质对DNA的损伤程度，提取汞物质与DNA相互作用的热力学和动力学信息，并为汞物质-DNA加合物的形成提供直接证据。汞物种与DNA的结合亲和力按Hg（II）< EtHg（I）类似于PhHg（I）类似于MeHg（I）的顺序增加。汞物种与DNA的相互作用遵循一级动力学和零级动力学的汞物种的DNA。汞与DNA碱基的内环和环外N位点高度共价配位。然而，DNA与汞物种的相互作用不会引起DNA原始构象的转变。结果表明，有机汞物种表现出更强的亲和力和更快的结合到DNA和显示更多的潜在损害比Hg（II）在动力学和热力学评价。此外，甲基汞（I）与DNA的结合速度最快，这表明甲基汞（I）在与DNA快速形成稳定复合物方面优于其他汞物种，而Hg（II）与DNA的结合速度最慢。本研究为汞与DNA的结合方式提供了新的证据和认识。
The interactions of inorganic mercury Hg(II), methylmercury (MeHg(I)), ethylmercury (EtHg(I)), and phenylmercury (PhHg(I)) with DNA have been probed by capillary electrophoresis with on-line electrothermal atomic absorption spectrometric detection (CE-ETAAS) in combination with circular dichroism and Fourier transform infrared spectroscopy. The CE-ETAAS assay allows sensitive probing of the level of DNA damage by mercury species, extraction of thermodynamic and kinetic information on the interactions of mercury species with DNA, and provides direct evidence for the formation of mercury species-DNA adducts. The binding affinity of mercury species to DNA increases in order of Hg(II) < EtHg(I) similar to PhHg(I) similar to MeHg(I). The interactions of mercury species with DNA follow a first-order kinetics for mercury species and zero-order kinetics for DNA. Mercury highly covalently coordinates to endocyclic and exocyclic N sites of DNA bases. However, the interactions of DNA with mercuric species cause no transition of the DNA original conformation. The results reveal that organomercuric species exhibit stronger affinity and faster binding to DNA and show more potential damage to DNA than Hg(II) in view of the kinetic and thermodynamic evaluations. Moreover, MeHg(I) exhibits the fastest binding to DNA, suggesting that MeHg(I) enjoys superiority over the other mercuric species for rapid formation of a stable complex with DNA, whereas Hg(II) shows the slowest binding to DNA. The present study provides new evidence and understanding of the binding modality of mercuric species to DNA.