Genetic Basis for Bacterial Mercury Methylation


Methylmercury is a potent neurotoxin produced from inorganic mercury by anaerobic bacteria in natural environments. Until now, however, the genes and proteins involved have remained unidentified. A team of scientists from Oak Ridge National Laboratory and collaborators from the Universities of Missouri and Tennessee identified a two-gene cluster required for mercury methylation by Desulfovibrio desulfuricans ND132 and Geobacter sulfurreducens PCA. In both bacteria, deletion of either or both genes resulted in the elimination of their ability to methylate mercury. Among bacteria and archaea with sequenced genomes, related genes (orthologs) are present in confirmed methylators but absent in non-methylators, suggesting a common mercury methylation pathway in all methylating bacteria and archaea sequenced to date.


Parks, J. M., A. Johs, M. Podar, R. Bridou, R. A. Hurt, S. D. Smith, S. J. Tomanicek, Y. Qian, S. D. Brown, C. C. Brandt, A. V. Palumbo, J. C. Smith, J. D. Wall, D. A. Elias, and L. Liang. 2013. “The Genetic Basis for Bacterial Mercury Methylation,” Science 339, 1332–35. DOI: 10.1126/science.1230667.