Essential anaplerotic role for the energy-converting hydrogenase Eha in hydrogenotrophic methanogenesis.

ABSTRACT: Despite decades of study, electron flow and energy conservation in methanogenic Archaea are still not thoroughly understood. For methanogens without cytochromes, flavin-based electron bifurcation has been proposed as an essential energy-conserving mechanism that couples exergonic and endergonic reactions of methanogenesis. However, an alternative hypothesis posits that the energy-converting hydrogenase Eha provides a chemiosmosis-driven electron input to the endergonic reaction. In vivo evidence for both hypotheses is incomplete. By genetically eliminating all nonessential pathways of H(2) metabolism in the model methanogen Methanococcus maripaludis and using formate as an additional electron donor, we isolate electron flow for methanogenesis from flux through Eha. We find that Eha does no

SUBMITTER: Lie TJ 

PROVIDER: S-EPMC3458328 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature