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Science 13 July 2007:
Vol. 317. no. 5835, pp. 225 - 227
DOI: 10.1126/science.1144314
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Reports

Cleaving Mercury-Alkyl Bonds: A Functional Model for Mercury Detoxification by MerB

Jonathan G. Melnick and Gerard Parkin*

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 [TmBut], which features three sulfur donors, has been used to synthesize [TmBut]HgR alkyl compounds (R = methyl or ethyl) that react with phenylthiol (PhSH) to yield [TmBut]HgSPh and RH. Although [TmBut]HgR compounds exist as linear two-coordinate complexes in the solid state, 1H nuclear magnetic resonance spectroscopy indicates that the complexes exist in rapid equilibrium with their higher-coordinate [{kappa}2-TmBut]HgR and [{kappa}3-TmBut]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.

Department of Chemistry, Columbia University, New York, NY 10027, USA.

* To whom correspondence should be addressed. E-mail: parkin{at}columbia.edu

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Crystal Structures of the Organomercurial Lyase MerB in Its Free and Mercury-bound Forms: INSIGHTS INTO THE MECHANISM OF METHYLMERCURY DEGRADATION.
J. Lafrance-Vanasse, M. Lefebvre, P. Di Lello, J. Sygusch, and J. G. Omichinski (2009)
J. Biol. Chem. 284, 938-944
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