title: The genome sequence of Geobacter metallireducens: features of metabolism, physiology and regulation common and dissimilar to Geobacter sulfurreducens.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  The 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.
  
  
  CONCLUSIONS
  The genomic evidence suggests that metabolism, physiology and regulation of gene expression in G. metallireducens may be dramatically different from other Geobacteraceae.
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, Amherst, MA, USA. muktak@microbio.umass.edu
authors.forename: Muktak
authors.initials: M
authors.lastname: Aklujkar
authors.forename: Julia
authors.initials: J
authors.lastname: Krushkal
authors.forename: Genevieve
authors.initials: G
authors.lastname: DiBartolo
authors.forename: Alla
authors.initials: A
authors.lastname: Lapidus
authors.forename: Miriam L
authors.initials: ML
authors.lastname: Land
authors.forename: Derek R
authors.initials: DR
authors.lastname: Lovley
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D045302:Geobacter / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C101050:ModE protein, bacteria; D014157:Transcription Factors