title: Methanogenic archaea: ecologically relevant differences in energy conservation.
abstract: Most methanogenic archaea can reduce CO(2) with H(2) to methane, and it is generally assumed that the reactions and mechanisms of energy conservation that are involved are largely the same in all methanogens. However, this does not take into account the fact that methanogens with cytochromes have considerably higher growth yields and threshold concentrations for H(2) than methanogens without cytochromes. These and other differences can be explained by the proposal outlined in this Review that in methanogens with cytochromes, the first and last steps in methanogenesis from CO(2) are coupled chemiosmotically, whereas in methanogens without cytochromes, these steps are energetically coupled by a cytoplasmic enzyme complex that mediates flavin-based electron bifurcation.
authors.affiliation: Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany. thauer@mpi-marburg.mpg.de
authors.forename: Rudolf K
authors.initials: RK
authors.lastname: Thauer
authors.forename: Anne-Kristin
authors.initials: AK
authors.lastname: Kaster
authors.forename: Henning
authors.initials: H
authors.lastname: Seedorf
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Buckel
authors.forename: Reiner
authors.initials: R
authors.lastname: Hedderich
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D019843:Archaeal Proteins / Q000235:genetics* / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism*; D019641:DNA, Archaeal / Q000235:genetics; D004734:Energy Metabolism; D019143:Evolution, Molecular; D019766:Genes, Archaeal / Q000235:genetics; D008697:Methane / Q000378:metabolism*; D010802:Phylogeny
chemical_list: D019843:Archaeal Proteins; D003580:Cytochromes; D019641:DNA, Archaeal; D008697:Methane