Abstract
BackgroundThe genome sequence of Geobacter metallireducens is the second to be completed from the metal-respiring genus Geobacter, and is compared in this report to that of Geobacter sulfurreducens in order to understand their metabolic, physiological and regulatory similarities and differences.ResultsThe experimentally observed greater metabolic versatility of G. metallireducens versus G. sulfurreducens is borne out by the presence of more numerous genes for metabolism of organic acids including acetate, propionate, and pyruvate. Although G. metallireducens lacks a dicarboxylic acid transporter, it has acquired a second putative succinate dehydrogenase/fumarate reductase complex, suggesting that respiration of fumarate was important until recently in its evolutionary history. Vestiges of the molybdate (ModE) regulon of G. sulfurreducens can be detected in G. metallireducens, which has lost the global regulatory protein ModE but retained some putative ModE-binding sites and multiplied certain genes of molybdenum cofactor biosynthesis. Several enzymes of amino acid metabolism are of different origin in the two species, but significant patterns of gene organization are conserved. Whereas most Geobacteraceae are predicted to obtain biosynthetic reducing equivalents from electron transfer pathways via a ferredoxin oxidoreductase, G. metallireducens can derive them from the oxidative pentose phosphate pathway. In addition to the evidence of greater metabolic versatility, the G. metallireducens genome is also remarkable for the abundance of multicopy nucleotide sequences found in intergenic regions and even within genes.ConclusionThe genomic evidence suggests that metabolism, physiology and regulation of gene expression in G. metallireducens may be dramatically different from other Geobacteraceae.
Highlights
The genome sequence of Geobacter metallireducens is the second to be completed from the metal-respiring genus Geobacter, and is compared in this report to that of Geobacter sulfurreducens in order to understand their metabolic, physiological and regulatory similarities and differences
Geobacter metallireducens is a member of the Geobacteraceae, a family of Fe(III)-respiring Delta-proteobacteria that are of interest for their role in cycling of carbon and metals in aquatic sediments and subsurface environments as well as the bioremediation of organic- and metal-contaminated groundwater and the harvesting of electricity from complex organic matter [1,2]
G. metallireducens is of particular interest because it was the first microorganism found to be capable of a number of novel anaerobic processes including: (1) conservation of energy to support growth from the oxidation of organic compounds coupled to the reduction of Fe(III) or Mn(IV) [3,4]; (2) conversion of Fe(III) oxide to ultrafine-grained magnetite [3]; (3) anaerobic oxidation of an aromatic hydrocarbon [5,6]; (4) reduction of U(VI) [7]; (5) use of humic substances as an electron acceptor [8]; (6) chemotaxis toward metals [9]; (7) complete oxidation of organic compounds to carbon dioxide with an electrode serving as the sole electron acceptor ([10]; and (8) use of a poised electrode as a direct electron donor [11]
Summary
The genome sequence of Geobacter metallireducens is the second to be completed from the metal-respiring genus Geobacter, and is compared in this report to that of Geobacter sulfurreducens in order to understand their metabolic, physiological and regulatory similarities and differences. In order to gain broader insight into the physiological diversity of Geobacter species, the genome of G. metallireducens was sequenced and compared to that of Geobacter sulfurreducens [12]. Both genome annotations were manually curated with the addition, removal and adjustment of hundreds of protein-coding genes and other features. This paper presents insights into the conserved and unique features of two Geobacter species, the metabolic versatility of G. metallireducens and the numerous families of multicopy nucleotide sequences in its genome, which suggest that regulation of gene expression is very different in these two species
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
