Biological Catalysis: Enzyme Mechanisms

Mercury is an environmental toxin due to its unusually strong affinity for thiols and other functional groups. Certain bacteria are able to convert Hg(II) species to less toxic Hg(0). Two of the critical enzymes in this process are the organomercurial lyase (MerB), which is responsible for breaking Hg-C bonds in organomercurials such as methylmercury, and the mercuric reductase (MerA), which catalyzes the conversion of Hg(II) to Hg(0).

We are interested in understanding the mechanism of bacterial mercury resistance using computer simulations. These approaches include density functional theory (DFT), classical molecular dynamics (MD), and combined quantum mechanical/molecular mechanical (QM/MM) methods. Our initial goal is to determine the mechanism of Hg-C bond cleavage catalyzed by MerB using quantum chemical calculations.