Alkylmercury lyase (EC:4.99.1.2) cleaves the carbon-mercury bond of organomercurials such as phenylmercuric acetate. This is the N terminal helix-turn-helix domain associated with Pfam:PF03243.
Mercury is a highly toxic metal. Toxicity can result from three different mercurial forms: elemental, inorganic ion and organomercurial compounds. The ability of bacteria to detoxify mercurial compounds by reduction and volatilisation is conferred by the Mer genes. Organomercurial lyase (MerB), also known as alkylmercury lyase, mediates the first of the two steps in the microbial detoxification of organomercurial salts (the other catalysed by mercuric reductase). It catalyses the protonolysis of the carbon-mercury bond in a wide range of organomercurial salts (primary, secondary, tertiary, alkyl, vinyl, allyl and aryl) to Hg(II) and the respective organic compound [PMID: 10548738]. Hg(II) is subsequently detoxified by mercuric reductase MerA.
