Geobacter sulfurreducens utilizes extracellular electron acceptors such as Mn(IV), Fe(III), syntrophic partners, and electrodes that vary from +0.4 to -0.3 V versus standard hydrogen electrode (SHE), representing a potential energy span that should require a highly branched electron transfer chain. Here we describe CbcBA, a bc-type cytochrome essential near the thermodynamic limit of respiration when acetate is the electron donor. Mutants-lacking cbcBA ceased Fe(III) reduction at -0.21 V versus SHE, could not transfer electrons to electrodes between -0.21 and -0.28 V, and could not reduce the final 10%-35% of Fe(III) minerals. As redox potential decreased during Fe(III) reduction, cbcBA was induced with the aid of the regulator BccR to become one of the most highly expressed genes in G. sulfurreducens. Growth yield (CFU/mM Fe(II)) was 112% of WT in ∆cbcBA, and deletion of cbcL (an unrelated bc-cytochrome essential near -0.15 V) in ΔcbcBA increased yield to 220%. Together with ImcH, which is required at high redox potentials, CbcBA represents a third cytoplasmic membrane oxidoreductase in G. sulfurreducens. This expanding list shows how metal-reducing bacteria may constantly sense redox potential to adjust growth efficiency in c...Continue Reading
Geobacter sulfurreducens sp. nov., a hydrogen- and acetate-oxidizing dissimilatory metal-reducing microorganism.
Geobacter metallireducens gen. nov. sp. nov., a microorganism capable of coupling the complete oxidation of organic compounds to the reduction of iron and other metals
Cloning and sequence of cymA, a gene encoding a tetraheme cytochrome c required for reduction of iron(III), fumarate, and nitrate by Shewanella putrefaciens MR-1
Identification of histidine residues in Wolinella succinogenes hydrogenase that are essential for menaquinone reduction by H2
Predicting transmembrane protein topology with a hidden Markov model: application to complete genomes
Biochemical and genetic characterization of PpcA, a periplasmic c-type cytochrome in Geobacter sulfurreducens
Stimulating the in situ activity of Geobacter species to remove uranium from the groundwater of a uranium-contaminated aquifer.
Characterization of the menaquinone reduction site in the diheme cytochrome b membrane anchor of Wolinella succinogenes NiFe-hydrogenase.
Novel mode of microbial energy metabolism: organic carbon oxidation coupled to dissimilatory reduction of iron or manganese.
The proteome of dissimilatory metal-reducing microorganism Geobacter sulfurreducens under various growth conditions
Computational prediction of RpoS and RpoD regulatory sites in Geobacter sulfurreducens using sequence and gene expression information
Diversity of promoter elements in a Geobacter sulfurreducens mutant adapted to disruption in electron transfer.
Microbial biofilm voltammetry: direct electrochemical characterization of catalytic electrode-attached biofilms
The organisation of proton motive and non-proton motive redox loops in prokaryotic respiratory systems
Respiration of Escherichia coli can be fully uncoupled via the nonelectrogenic terminal cytochrome bd-II oxidase.
GSEL version 2, an online genome-wide query system of operon organization and regulatory sequence elements of Geobacter sulfurreducens
Genome-wide gene regulation of biosynthesis and energy generation by a novel transcriptional repressor in Geobacter species.
Substrate-level phosphorylation is the primary source of energy conservation during anaerobic respiration of Shewanella oneidensis strain MR-1.
PSORTb 3.0: improved protein subcellular localization prediction with refined localization subcategories and predictive capabilities for all prokaryotes.
Silent mischief: bacteriophage Mu insertions contaminate products of Escherichia coli random mutagenesis performed using suicidal transposon delivery plasmids mobilized by broad-host-range RP4 conjugative machinery
A functional description of CymA, an electron-transfer hub supporting anaerobic respiratory flexibility in Shewanella.
Revision of iron(III)-citrate speciation in aqueous solution. Voltammetric and spectrophotometric studies
Proteins involved in electron transfer to Fe(III) and Mn(IV) oxides by Geobacter sulfurreducens and Geobacter uraniireducens
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