%0 Journal Article
%T More Than 200 Genes Required for Methane Formation from H2 and CO2 and Energy Conservation Are Present in Methanothermobacter marburgensis and Methanothermobacter thermautotrophicus
%A Anne-Kristin Kaster
%A Meike Goenrich
%A Henning Seedorf
%A Heiko Liesegang
%A Antje Wollherr
%A Gerhard Gottschalk
%A Rudolf K. Thauer
%J Archaea
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/973848
%X The hydrogenotrophic methanogens Methanothermobacter marburgensis and Methanothermobacter thermautotrophicus can easily be mass cultured. They have therefore been used almost exclusively to study the biochemistry of methanogenesis from H2 and CO2, and the genomes of these two model organisms have been sequenced. The close relationship of the two organisms is reflected in their genomic architecture and coding potential. Within the 1,607 protein coding sequences (CDS) in common, we identified approximately 200 CDS required for the synthesis of the enzymes, coenzymes, and prosthetic groups involved in CO2 reduction to methane and in coupling this process with the phosphorylation of ADP. Approximately 20 additional genes, such as those for the biosynthesis of F430 and methanofuran and for the posttranslational modifications of the two methyl-coenzyme M reductases, remain to be identified. 1. Introduction In 1972, Zeikus and Wolfe [1] isolated Methanothermobacter thermautotrophicus (DSM 1053) (formerly Methanobacterium thermoautotrophicum strain ¦¤H) from sludge from the anaerobic sewage digestion plant in Urbana, Illinois, USA. This thermophile grew on H2 and CO2 as sole energy source (reaction 1) and CO2 as sole carbon source with doubling times of less than 5£¿h and to very high cell concentrations (1.5£¿g cells (dry mass) per L). For the first time, it became possible to obtain sufficient cell mass of a hydrogenotrophic methanogen for the purification of enzymes and coenzymes involved in CO2 reduction to methane. In 1978, Fuchs et al. [2] reported the isolation of Methanothermobacter marburgensis (DSM 2133) (formerly Methanobacterium thermoautotrophicum strain Marburg) from anaerobic sewage sludge in Marburg, Germany. The Marburg strain grew on H2 and CO2 even faster (doubling time less than 2£¿h) and to even higher cell concentrations (3£¿g cells (dry mass) per L) than the ¦¤H strain and was, therefore, subsequently used in Marburg and elsewhere for the study of methanogenesis. Most of what is presently known about the biochemistry of CO2 reduction to methane with H2 was worked out with either M. thermautotrophicus [3] or M. marburgensis [4¨C6] ( calculated for H2, CO2, and CH4 in the gas phase). The genome of M. thermautotrophicus (NC_000916) was one of the first genomes of Archaea to be sequenced [7] and that of M. marburgensis (NC_014408/CP001710) has just recently been announced [8]. This paper concentrates on the analysis of protein-coding sequences (CDS) required for the synthesis of enzymes, coenzymes, and prosthetic groups involved in CO2 reduction to
%U http://www.hindawi.com/journals/archaea/2011/973848/