title: Dissimilatory reduction of extracellular electron acceptors in anaerobic respiration.
abstract: An extension of the respiratory chain to the cell surface is necessary to reduce extracellular electron acceptors like ferric iron or manganese oxides. In the past few years, more and more compounds were revealed to be reduced at the surface of the outer membrane of Gram-negative bacteria, and the list does not seem to have an end so far. Shewanella as well as Geobacter strains are model organisms to discover the biochemistry that enables the dissimilatory reduction of extracellular electron acceptors. In both cases, c-type cytochromes are essential electron-transferring proteins. They make the journey of respiratory electrons from the cytoplasmic membrane through periplasm and over the outer membrane possible. Outer membrane cytochromes have the ability to catalyze the last step of the respiratory chains. Still, recent discoveries provided evidence that they are accompanied by further factors that allow or at least facilitate extracellular reduction. This review gives a condensed overview of our current knowledge of extracellular respiration, highlights recent discoveries, and discusses critically the influence of different strategies for terminal electron transfer reactions.
authors.affiliation: Institut für Angewandte Biowissenschaften, Angewandte Biologie, Karlsruher Institut für Technologie, Karlsruhe, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Richter
authors.forename: Marcus
authors.initials: M
authors.lastname: Schicklberger
authors.forename: Johannes
authors.initials: J
authors.lastname: Gescher
mesh_terms: D000693:Anaerobiosis; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D004579:Electron Transport; D005290:Ferric Compounds / Q000378:metabolism*; D006090:Gram-Negative Bacteria / Q000378:metabolism*; D017895:Manganese Compounds / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D010084:Oxidation-Reduction; D010087:Oxides / Q000378:metabolism*; D033903:Periplasmic Proteins / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D005290:Ferric Compounds; D017895:Manganese Compounds; D008565:Membrane Proteins; D010087:Oxides; D033903:Periplasmic Proteins; C027424:manganese oxide