title: Metabolic flexibility revealed in the genome of the cyst-forming alpha-1 proteobacterium Rhodospirillum centenum.
abstract: BACKGROUND
  Rhodospirillum centenum is a photosynthetic non-sulfur purple bacterium that favors growth in an anoxygenic, photosynthetic N2-fixing environment. It is emerging as a genetically amenable model organism for molecular genetic analysis of cyst formation, photosynthesis, phototaxis, and cellular development. Here, we present an analysis of the genome of this bacterium.
  
  
  RESULTS
  R. centenum contains a singular circular chromosome of 4,355,548 base pairs in size harboring 4,105 genes. It has an intact Calvin cycle with two forms of Rubisco, as well as a gene encoding phosphoenolpyruvate carboxylase (PEPC) for mixotrophic CO2 fixation. This dual carbon-fixation system may be required for regulating internal carbon flux to facilitate bacterial nitrogen assimilation. Enzymatic reactions associated with arsenate and mercuric detoxification are rare or unique compared to other purple bacteria. Among numerous newly identified signal transduction proteins, of particular interest is a putative bacteriophytochrome that is phylogenetically distinct from a previously characterized R. centenum phytochrome, Ppr. Genes encoding proteins involved in chemotaxis as well as a sophisticated dual flagellar system have also been mapped.
  
  
  CONCLUSIONS
  Remarkable metabolic versatility and a superior capability for photoautotrophic carbon assimilation is evident in R. centenum.
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Yih-Kuang
authors.initials: YK
authors.lastname: Lu
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Marden
authors.forename: Mira
authors.initials: M
authors.lastname: Han
authors.forename: Wesley D
authors.initials: WD
authors.lastname: Swingley
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Mastrian
authors.forename: Sugata Roy
authors.initials: SR
authors.lastname: Chowdhury
authors.forename: Jicheng
authors.initials: J
authors.lastname: Hao
authors.forename: Tamer
authors.initials: T
authors.lastname: Helmy
authors.forename: Sun
authors.initials: S
authors.lastname: Kim
authors.forename: Ahmet A
authors.initials: AA
authors.lastname: Kurdoglu
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Matthies
authors.forename: David
authors.initials: D
authors.lastname: Rollo
authors.forename: Paul
authors.initials: P
authors.lastname: Stothard
authors.forename: Robert E
authors.initials: RE
authors.lastname: Blankenship
authors.forename: Carl E
authors.initials: CE
authors.lastname: Bauer
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Touchman
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D002633:Chemotaxis / Q000235:genetics; D002734:Chlorophyll / Q000096:biosynthesis; D005407:Flagella / Q000235:genetics / Q000378:metabolism; D016680:Genome, Bacterial / Q000235:genetics*; D020283:Photoreceptors, Microbial / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis / Q000235:genetics; D042182:Rhodospirillum centenum / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; D002734:Chlorophyll; D002244:Carbon