The genome of the RC-I archaeon is made from 3.2 million base pairs, and codes for 3,103 proteins. The proteins can, among other things, be organized according to their methanogenic metabolism - that is, how they create methane simply by reducing carbon dioxide with hydrogen. Enzymes for the analysis of alternative methanogenic nutrients are not encoded by the RC-I genome. The RC-I archaeon can thus be categorised as hydrogenotroph Methanogenic Archaea can only produce methane, and the energy that comes from it, when oxygen is completely absent. The presence of oxygen is normally very hostile to them. However, this is not the case for RC-I Archaea - the RC-I genome codes for enzymatic mechanisms which are unique for methanogenic Archaea and make it possible for them to survive in an oxygenated environment. A whole group of enzymes belongs to this mechanism. These enzymes quickly detoxify highly reactive oxygen species, such as superoxide anion or hydrogen peroxide. These oxygen species are extremely toxic for living cells. When oxygen is present, RC-I Archaea quickly switch to a zymoma fermentative.

Sequencing the RC-I genome offers the groundwork for developing a means of monitoring the activity of RC-I Archaea in their natural environments, using molecular biological methods. It is uncertain, however, how long it will take before we can actually reduce the methane production of RC-I Archaea -- and methane emissions from places like rice paddies.

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Contact: Dr. Werner Liesack
Liesack@mpi-marburg.mpg.de
0049-642-117-8720
Max-Planck-Gesellschaft
3-Aug-2006