title: Altered residues in key proteins influence the expression and activity of the nitrogenase complex in an adaptive CO2 fixation-deficient mutant strain of Rhodobacter sphaeroides.
abstract: Previously, the RubisCO-compromised spontaneous adaptive Rhodobacter sphaeroides mutant, strain 16PHC, was shown to derepress the expression of genes that encode the nitrogenase complex under normal repressive conditions. As a result of this adaptation, the active nitrogenase complex restored redox balance, thus allowing strain 16PHC to grow under photoheterotrophic conditions in the absence of an exogenous electron acceptor. A combination of whole genome pyrosequencing and whole genome microarray analyses was employed to identify possible loci responsible for the observed phenotype. Mutations were found in two genes, glnA and nifA, whose products are involved in the regulatory cascade that controls nitrogenase complex gene expression. In addition, a nucleotide reversion within the nifK gene, which encodes a subunit of the nitrogenase complex, was also identified. Subsequent genetic, physiological and biochemical studies revealed alterations that led to derepression of the synthesis of an active nitrogenase complex in strain 16PHC.
authors.affiliation: Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Farmer
authors.affiliation: Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Rick
authors.initials: R
authors.lastname: Laguna
authors.affiliation: Plant-Microbe Genomics Facility, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Jenny
authors.initials: J
authors.lastname: Panescu
authors.affiliation: Plant-Microbe Genomics Facility, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: McCoy
authors.affiliation: Plant-Microbe Genomics Facility, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Beth
authors.initials: B
authors.lastname: Logsdon
authors.affiliation: Plant-Microbe Genomics Facility, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Mike
authors.initials: M
authors.lastname: Zianni
authors.affiliation: Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Moskvin
authors.affiliation: Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Gomelsky
authors.affiliation: Plant-Microbe Genomics Facility, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.|Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: F Robert
authors.initials: FR
authors.lastname: Tabita
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004252:DNA Mutational Analysis; D056426:Genetic Loci; D016680:Genome, Bacterial; D046228:Microarray Analysis; D009154:Mutation; D009591:Nitrogenase / Q000235:genetics* / Q000378:metabolism*; D010084:Oxidation-Reduction; D012242:Rhodobacter sphaeroides / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D009591:Nitrogenase