A possible molecular link between the toxicological effects of arsenic, selenium and methylmercury: methylmercury(II) seleno bis(S-glutathionyl) arsenic(III).

Using a combination of As and Se K-edge and Hg L(III)-edge X-ray absorption spectroscopy, 77Se nuclear magnetic resonance spectroscopy, electrospray ionization mass spectrometry and molecular modeling, we have structurally characterized the novel species methylmercury(II) seleno bis(S-glutathionyl) arsenic(III). This species is formed in aqueous solution from CH3HgOH and the seleno bis(S-glutathionyl) arsinium ion and constitutes an important first step towards characterizing the observed toxicologically relevant interaction between arsenite, selenite and methylmercury which has been previously reported in mammals.