Bacteria Genomes - METHYLOCOCCUS CAPSULATUS

Methylococcus capsulatus is a methanotroph (Methane-oxidising bacteria.) Methanotrophs are ubiquitous Gram-negative bacteria that can use the greenhouse gas methane as a sole carbon and energy source for growth, thus playing major roles in global carbon cycles, and in particular, substantially reducing emissions of biologically generated methane to the atmosphere.

Methanotrophs have attracted considerable interest over the past 20 years because of their potential in producing bulk chemicals (e.g. propylene oxide) and single-cell protein and for use in biotransformation. Methanotrophs are unique in that they only grow on methane, although some will also grow on methanol.

Methanotrophs are also able to metabolize or co-metabolize xenobiotic compounds, including chlorinated solvents such as trichloroethylene, and hence have potential as bioremediation tools.

Methylococcus capsulatus (Bath) is the first complete genome sequence reported from an obligate methanotroph. Genome analysis suggests the ability of M. capsulatus to scavenge copper (including a previously unreported nonribosomal peptide synthetase) and to use copper in regulation of methanotrophy, but the exact regulatory mechanisms remain unclear.

One surprising outcome of the genome project is evidence suggesting the existence of previously unsuspected metabolic flexibility in M. capsulatus, including an ability to grow on sugars, oxidize chemolithotrophic hydrogen and sulfur, and live under reduced oxygen tension, all of which have implications for methanotroph ecology. The availability of the complete genome of M. capsulatus (Bath) deepens our understanding of methanotroph biology and its relationship to global carbon cycles.

The genome of M. capsulatus (Bath) comprises a single circular molecule of 3,304,697 bp.

References:

PLoS Biol. 2:1616-1628 (2004)
Arch. Microbiol. 177 :167–172 (2002)
Appl Microbiol Biotechnol. 2002 Jun;59(1):33-9