The Genetic Basis for Bacterial Mercury Methylation

• DOI: 10.1126/science.1230667
• Publication Date: 2013-02-08T02:47:59Z
• Authors: Jerry M. Parks; Alexander Johs; Mircea Podar; Romain Bridou; Richard A. Hurt; Steven D. Smith; Stephen J. Tomanicek; Yun Qian; Steven D. Brown; Craig C. Brandt; Anthony V. Palumbo; Jeremy C. Smith; Judy D. Wall; Dwayne A. Elias; Liyuan Liang
• Keywords: Methylmercury; Mercury; Bacterial genome size

Mercury Methylating Microbes (Hg) most commonly becomes bioavailable and enters the food web as organic form methylmercury, where it induces acute toxicity effects that can be magnified up chain. But natural anthropogenic Hg exists inorganic 2+ is only transformed into methylmercury by anaerobic microorganisms—typically sulfur-reducing bacteria. Using comparative genomics, Parks et al. (p. 1332 , published online 7 February; see Perspective Poulain Barkay ) identified two genes encode a corrinoid iron-sulfur proteins in six known Hg-methylating bacteria but were absent nonmethylating In distantly related model bacteria, deletion of either gene—or both simultaneously—reduced ability for to produce did not impair cellular growth. The presence this two-gene cluster several other bacterial lineages which genome sequences are available suggests may more broadly distributed microbial world than previously recognized.