title: Something from almost nothing: carbon dioxide fixation in chemoautotrophs.
abstract: The last decade has seen significant advances in our understanding of the physiology, ecology, and molecular biology of chemoautotrophic bacteria. Many ecosystems are dependent on CO2 fixation by either free-living or symbiotic chemoautotrophs. CO2 fixation in the chemoautotroph occurs via the Calvin-Benson-Bassham cycle. The cycle is characterized by three unique enzymatic activities: ribulose bisphosphate carboxylase/oxygenase, phosphoribulokinase, and sedoheptulose bisphosphatase. Ribulose bisphosphate carboxylase/oxygenase is commonly found in the cytoplasm, but a number of bacteria package much of the enzyme into polyhedral organelles, the carboxysomes. The carboxysome genes are located adjacent to cbb genes, which are often, but not always, clustered in large operons. The availability of carbon and reduced substrates control the expression of cbb genes in concert with the LysR-type transcriptional regulator, CbbR. Additional regulatory proteins may also be involved. All of these, as well as related topics, are discussed in detail in this review.
authors.affiliation: Department of Biological Sciences, Clemson University, South Carolina 29634, USA. sjessup@clemson.edu
authors.forename: J M
authors.initials: JM
authors.lastname: Shively
authors.forename: G
authors.initials: G
authors.lastname: van Keulen
authors.forename: W G
authors.initials: WG
authors.lastname: Meijer
mesh_terms: D001426:Bacterial Proteins; D002245:Carbon Dioxide / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D005809:Genes, Regulator / Q000235:genetics; D006091:Gram-Negative Chemolithotrophic Bacteria / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D002479:Inclusion Bodies / Q000201:enzymology / Q000235:genetics; D009876:Operon / Q000235:genetics; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics / Q000378:metabolism; D013559:Symbiosis; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D002245:Carbon Dioxide; C072714:cfxR protein, bacteria; D017853:Phosphotransferases (Alcohol Group Acceptor); C022390:phosphoribulokinase; D010744:Phosphoric Monoester Hydrolases; C022627:sedoheptulose-bisphosphatase; D012273:Ribulose-Bisphosphate Carboxylase