The roles of outer membrane cytochromes of Shewanella and Geobacterin extracellular electron transfer

Shi, Liang, Richardson, David J. ORCID:, Wang, Zheming, Kerisit, Sebastien N., Rosso, Kevin M., Zachara, John M. and Fredrickson, James K. (2009) The roles of outer membrane cytochromes of Shewanella and Geobacterin extracellular electron transfer. Environmental Microbiology Reports, 1 (4). pp. 220-227. ISSN 1758-2229

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As key components of the electron transfer (ET) pathways used for dissimilatory reduction of solid iron [Fe(III)] (hydr)oxides, outer membrane multihaem c-type cytochromes MtrC and OmcA of Shewanella oneidensis MR-1 and OmcE and OmcS of Geobacter sulfurreducens mediate ET reactions extracellularly. Both MtrC and OmcA are at least partially exposed to the extracellular side of the outer membrane and their translocation across the outer membrane is mediated by bacterial type II secretion system. Purified MtrC and OmcA can bind Fe(III) oxides, such as haematite (α-Fe2O3), and directly transfer electrons to the haematite surface. Bindings of MtrC and OmcA to haematite are probably facilitated by their putative haematite-binding motifs whose conserved sequence is Thr–Pro–Ser/Thr. Purified MtrC and OmcA also exhibit broad operating potential ranges that make it thermodynamically feasible to transfer electrons directly not only to Fe(III) oxides but also to other extracellular substrates with different redox potentials. OmcE and OmcS are proposed to be located on the Geobacter cell surface where they are believed to function as intermediates to relay electrons to type IV pili, which are hypothesized to transfer electrons directly to the metal oxides. Cell surface-localized cytochromes thus are key components mediating extracellular ET reactions in both Shewanella and Geobacter for extracellular reduction of Fe(III) oxides.

Item Type: Article
Faculty \ School: Faculty of Science > School of Biological Sciences
UEA Research Groups: Faculty of Science > Research Groups > Organisms and the Environment
Faculty of Science > Research Groups > Molecular Microbiology
Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry
Depositing User: Users 2731 not found.
Date Deposited: 01 Feb 2011 13:04
Last Modified: 15 May 2023 07:30
DOI: 10.1111/J.1758-2229.2009.00035.X

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