Cleaving mercury-alkyl bonds:: A functional model for mercury detoxification by MerB
Cleaving mercury-alkyl bonds:: A functional model for mercury detoxification by MerB
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DOI：
10.1126/science.1144314
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发表时间：
2007-07-13
期刊：
影响因子：
56.9
通讯作者：
Parkin, Gerard
中科院分区：
文献类型：
--
作者：
Melnick, Jonathan G.;Parkin, Gerard
在环境中发现的有机汞化合物的极端毒性已经将注意力集中在细菌修复酶的作用机制上。我们描述了简易的室温质子裂解的汞-烷基化合物，模仿的结构和功能的有机汞裂解酶MerB的汞-C键的硫醇。具体而言，具有三个硫供体的三（2-巯基-1-叔丁基咪唑基）硼氢化配体[Tm-But]已用于合成[Tm-But] HgR烷基化合物（R =甲基或乙基），其与苯硫醇（PhSH）反应产生[Tm-But] HgSPh和RH。虽然[Tm-But] HgR化合物在固态下以线性二配位络合物形式存在，但H-1核磁共振谱表明，该络合物在溶液中与其更高配位的[kappa（2）-Tm-But] HgR和[kappa（3）-Tm-But] HgR异构体存在快速平衡。建议容易获得更高配位的物种，以解释[ TmBut] HgR相对于其他二配位汞烷基化合物的异常反应性。
The extreme toxicity of organomercury compounds that are found in the environment has focused attention on the mechanisms of action of bacterial remediating enzymes. We describe facile room-temperature protolytic cleavage by a thiol of the Hg-C bond in mercury-alkyl compounds that emulate the structure and function of the organomercurial lyase MerB. Specifically, the tris( 2-mercapto-1-t-butylimidazolyl) hydroborato ligand [Tm-But], which features three sulfur donors, has been used to synthesize [Tm-But] HgR alkyl compounds (R = methyl or ethyl) that react with phenylthiol (PhSH) to yield [Tm-But] HgSPh and RH. Although [Tm-But] HgR compounds exist as linear two-coordinate complexes in the solid state, H-1 nuclear magnetic resonance spectroscopy indicates that the complexes exist in rapid equilibrium with their higher-coordinate [kappa(2)-Tm-But] HgR and [kappa(3)-Tm-But] HgR isomers in solution. Facile access to a higher-coordinate species is proposed to account for the exceptional reactivity of [ TmBut] HgR relative to that of other two-coordinate mercury-alkyl compounds.