Response to mercury (II) ions in Methylococcus capsulatus (Bath)

R Boden, JC Murrell

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

The mercury (II) ion is toxic and is usually detoxified in Bacteria by reduction to elemental mercury, which is less toxic. This is catalysed by an NAD(P)H-dependent mercuric reductase (EC 1.16.1.1). Here, we present strong evidence that Methylococcus capsulatus (Bath) – a methanotrophic member of the Gammaproteobacteria – uses this enzyme to detoxify mercury. In radiorespirometry studies, it was found that cells exposed to mercury dissimilated 100% of [14C]-methane provided to generate reducing equivalents to fuel mercury (II) reduction, rather than the mix of assimilation and dissimilation found in control incubations. The detoxification system is constitutively expressed with a specific activity of 352 (±18) nmol NADH oxidized min-1 (mg protein)-1. Putative mercuric reductase genes were predicted in the M. capsulatus (Bath) genome and found in mRNA microarray studies. The MerA-derived polypeptide showed high identity (> 80%) with MerA sequences from the Betaproteobacteria.
Original languageEnglish
Pages (from-to)106-110
Number of pages5
JournalFEMS Microbiology Letters
Volume324
Issue number2
DOIs
Publication statusPublished - Nov 2011

Cite this