Project description:Aquifex aeolicus is a microaerophilic hydrogen- and sulfur -oxidizing bacterium that assimilates CO2 via the reverse tricarboxylic acid cycle (rTCA). Key enzymes of this pathway are pyruvate:ferredoxin oxidoreductase (PFOR) and 2-oxoglutarate:ferredoxin oxidoreductase (OGOR), which are responsible, respectively, for the reductive carboxylation of acetyl-CoA to pyruvate and of succinyl-CoA to 2-oxoglutarate, two energetically unfavorable reactions that require a strong reduction potential. We have confirmed, by biochemistry and proteomics, that A. aeolicus possesses a pentameric version of these enzyme complexes ((αβγδε)2) and that they are highly abundant in the cell. In addition, we have purified and characterized from the soluble fraction of A. aeolicus, two low redox potential and oxygen-stable [4Fe-4S] ferredoxins (Fd6 and Fd7, E0 = -440 and -460 mV respectively) and have shown that they can physically interact and exchange electrons with both PFOR and OGOR, suggesting that they could be the physiological electron donors of the system in vivo. Shotgun proteomics indicated that all the enzymes assumed to be involved in the rTCA cycle are produced in the A. aeolicus cells. A number of additional enzymes, previously suggested to be part of a putative partial Wood-Ljungdahl pathway used for the synthesis of serine and glycine from CO2 [1], were identified by mass spectrometry, but their abundance in the cell seem to be much lower than those of the rTCA cycle. Their possible involvement in the carbon assimilation is discussed. 1- Braakman, R.; Smith, E. Metabolic Evolution of a Deep-Branching Hyperthermophilic Chemoautotrophic Bacterium. PloS One 2014, 9, e87950, doi:10.1371/journal.pone.0087950.
Project description:This SuperSeries is composed of the following subset Series: GSE28549: Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus placidus (Phenol vs. Benzoate) GSE30798: Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus placidus (Benzene vs. Acetate) GSE30799: Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus placidus (Benzene vs. Phenol) GSE30801: Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus placidus (Benzene vs. Benzoate) Refer to individual Series
Project description:Although proteins and peptides encoded in small open reading frames (ORFs < 100 AA) in microbial genomes can play critical roles as toxins, bacteriocins, transcriptional regulators, signaling molecules, and chaperones, many such ORFs remain annotated as “hypothetical proteins”. In the genome of the hyperthermophilic bacterium, Thermotoga maritima, nearly 2/3 of the 167 small ORFs have no known function. As a strategy for investigating the potential significance of specific small ORFs, growth conditions that could trigger the expression of genes encoding small ORFs were sought. A defined medium supplemented with either 1 or 5 g/L yeast extract was used to track transcriptional response during the transition from exponential to stationary phase.
Project description:In this study, we generated allelic knockouts of ATP-dependent RNA ligase (Rnl) in hyperthermophilic archaeon T. kodakarensis and analyze the small RNAs.
