量子化学研究Cd^(2+)、Hg^(2+)、Pb^(2+)与谷胱甘肽相互作用

Investigation on the interaction of Cd^(2+),Hg^(2+) and Pb^(2+) with glutathione by quantum chemistry calculation

采用密度泛函DFT/B3LYP方法研究了重金属离子(Cd^(2+),Hg^(2+),Pb^(2+))与生物分子谷胱甘肽相(GSH)互作用位点及形成复合物的结构。结果显示:Cd^(2+)、Hg^(2+)和Pb^(2+)都能与GSH电负性原子(N,S,O)形成9种稳定的复合物,而且与GSH相互作用过程中对S原子表现出很强的结合能力;Cd^(2+)、Hg^(2+)和Pb^(2+)在与GSH结合的过程中不同程度的破坏了GSH分子内氢键,使氢质子发生迁移;pb^(2+)与GSH的结合能最小,但和S原子之间成键的共价性最强;从复合物中金属离子的电子组态分布来看Hg^(2+)有被还原为Hg^+的趋势。

The interaction of Cd^2＋, Hg^2＋and Pb^2＋ with glutathione （GSH） was systematically investigated employing the density function theory DFT/B3LYP, the site of interaction and the structure of the complexes were taken into account. The results showed that： Cd^2＋, Hg^2＋and Pb^2＋ exhibited high affinities to the S atom of GSH, and the interaction of metal ions with the electronegative atoms （N, S, and O） of GSH gave nine stable complexes. The intramolecular hydrogen bond was broken or promoted to migrate during the coordination reaction. The binding energy of Pb^2＋ with GSH was lowest among the metals, the bonds between pb^2＋and S had more covalent contribution than that of Cd^2＋ and Hg^2＋. Furthermore, Hg^2＋ had the tendency to be reduced to Hg^＋ during the coordination with GSH.