The alternative complex III: A different architecture using known building modules

Refojo, Patrícia N.; Sousa, Filipa L.; Teixeira, Miguel; Pereira, Manuela M.

doi:10.1016/j.bbabio.2010.04.012

Cited by 55 publications

(54 citation statements)

References 45 publications

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“…Furthermore, the genes coding for another crucial complex of aerobic respiratory electron transfer chain-the cytochrome bc 1 complex-are absent, along with homologues of the alternative Complex III (Refojo et al, 2010), confirming the inability of this organism for oxygen respiration. Cytochrome bd ubiquinol oxidase, present in HSR2 (HLASF_0492-0493), likely serves for oxygen detoxification, similarly to oxidases of other strict anaerobes, such as acetogens and sulfate reducers (Jünemann, 1997).…”

Section: Genetic Determinants Of Acetate Oxidation and Respiratory Chainmentioning

confidence: 91%

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon

et al. 2015

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Archaea domain is comprised of many versatile taxa that often colonize extreme habitats. Here, we report the discovery of strictly anaerobic extremely halophilic euryarchaeon, capable of obtaining energy by dissimilatory reduction of elemental sulfur using acetate as the only electron donor and forming sulfide and CO 2 as the only products. This type of respiration has never been observed in hypersaline anoxic habitats and is the first example of such metabolic capability in the entire Archaea domain. We isolated and cultivated these unusual organisms, selecting one representative strain, HSR2, for detailed characterization. Our studies including physiological tests, genome sequencing, gene expression, metabolomics and [ 14 C]-bicarbonate assimilation assays revealed that HSR2 oxidized acetate completely via the tricarboxylic acid cycle. Anabolic assimilation of acetate occurred via activated glyoxylate bypass and anaplerotic carboxylation. HSR2 possessed sulfurtransferase and an array of membrane-bound polysulfide reductase genes, all of which were expressed during the growth. Our findings suggest the biogeochemical contribution of haloarchaea in hypersaline anoxic environments must be reconsidered.

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Section: Genetic Determinants Of Acetate Oxidation and Respiratory Chainmentioning

confidence: 91%

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon

et al. 2015

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“…Following the recent discovery of ACIII, there are questions regarding its function even though there have been important advancements from the model organisms Chloroflexus aurantiacus, a filamentous, anoxygenic phototroph, and Rhodothermus marinus, a marine heterotroph (34)(35)(36). The actB genes in these microorganisms encode a large protein that contains domains with homology to a molybdopterin-guanine dinucleotide-containing catalytic subunit in the complex of iron-sulfur molybdoenzyme (CISM) family (domain 1) and to an iron-sulfur protein in the CISM family (domain 2).…”

Section: Resultsmentioning

confidence: 99%

“…However, peptides for this bc 1 complex are present at relatively low levels in this proteomic profile. Alternatively, it is hypothesized that this function could potentially be performed by ACIII, which has been shown to be an analog of the bc 1 complex (34)(35)(36) and is represented in the profile by a large number of peptides. A recent report (61) presents a remarkably similar model, including reverse electron transport via ACIII, in an uncultivated nonphotosynthetic member of the Chromatiaceae that is capable of growing on biocathodes.…”

Section: Resultsmentioning

confidence: 99%

New Insight into Microbial Iron Oxidation as Revealed by the Proteomic Profile of an Obligate Iron-Oxidizing Chemolithoautotroph

Barco

Emerson

Sylvan

et al. 2015

Appl Environ Microbiol

129

150

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Microaerophilic, neutrophilic, iron-oxidizing bacteria (FeOB) grow via the oxidation of reduced Fe(II) at or near neutral pH, in the presence of oxygen, making them relevant in numerous environments with elevated Fe(II) concentrations. However, the biochemical mechanisms for Fe(II) oxidation by these neutrophilic FeOB are unknown, and genetic markers for this process are unavailable. In the ocean, microaerophilic microorganisms in the genus Mariprofundus of the class Zetaproteobacteria are the only organisms known to chemolithoautotrophically oxidize Fe and concurrently biomineralize it in the form of twisted stalks of iron oxyhydroxides. The aim of this study was to identify highly expressed proteins associated with the electron transport chain of microaerophilic, neutrophilic FeOB. To this end, Mariprofundus ferrooxydans PV-1 was cultivated, and its proteins were extracted, assayed for redox activity, and analyzed via liquid chromatography-tandem mass spectrometry for identification of peptides. The results indicate that a cytochrome c 4 , cbb 3 -type cytochrome oxidase subunits, and an outer membrane cytochrome c were among the most highly expressed proteins and suggest an involvement in the process of aerobic, neutrophilic bacterial Fe oxidation. Proteins associated with alternative complex III, phosphate transport, carbon fixation, and biofilm formation were abundant, consistent with the lifestyle of Mariprofundus. Iron (Fe) is one of the most abundant elements on Earth and a major component of the oceanic crust (1). The biologically catalyzed oxidation of Fe at circumneutral pH with oxygen (O 2 ) as the terminal electron acceptor has remained largely enigmatic, even though neutrophilic Fe oxidation is among the first chemoautotrophic microbial metabolisms described in the literature (2). This lack of data is due, in part, to obstacles such as culturing of fastidious microaerophilic, neutrophilic, Fe-oxidizing bacteria (FeOB); the relatively low cell densities in cultures; and the interference of Fe oxides with sample preparation. In addition to this, aerobic, neutrophilic FeOB have so far been elusive to genetic manipulation. Consequently, these challenges have impeded the ability to understand the mechanisms of neutrophilic Fe oxidation in the presence of O 2 and inhibited the development of molecular diagnostics targeting genetic markers for such a biological function (i.e., molecular probes targeting genes, transcripts, or proteins indicative of activity). Recent genomic analyses of microaerophilic, neutrophilic FeOB (3-6) have suggested genes that might be involved in Fe oxidation; however, evidence of expression of these genes in FeOB has not been shown. This is in contrast with the recent advancements in the elucidation of the mechanisms of Fe oxidation in aerobic, acidophilic bacteria (especially Acidithiobacillus ferrooxidans and Leptospirillum spp.) and neutrophilic, anoxygenic, phototrophic bacteria (Rhodopseudomonas palustris and Rhodobacter spp.) (see reference 7 for a review).Mariprofundus fer...

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“…Hence, the genes encoding menaquinone biosynthesis, cytochrome c, ATP synthase, and NADH dehydrogenases are all present. The genes actABCDEF and ccsBA encoding the recently described components of the alternative complex III menaquinol-cytochrome c oxidoreductase (45) and the components of system II cytochrome c synthetase and heme channel (15), respectively, are also present in the FL-15 genome.…”

Section: ϫ5mentioning

confidence: 99%

Complete Genome Sequence of the Fish Pathogen Flavobacterium branchiophilum

Touchon

Barbier

Bernardet

et al. 2011

Appl Environ Microbiol

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Members of the genus Flavobacterium occur in a variety of ecological niches and represent an interesting diversity of lifestyles. Flavobacterium branchiophilum is the main causative agent of bacterial gill disease, a severe condition affecting various cultured freshwater fish species worldwide, in particular salmonids in Canada and Japan. We report here the complete genome sequence of strain FL-15 isolated from a diseased sheatfish (Silurus glanis) in Hungary. The analysis of the F. branchiophilum genome revealed putative mechanisms of pathogenicity strikingly different from those of the other, closely related fish pathogen Flavobacterium psychrophilum, including the first cholera-like toxin in a non-Proteobacteria and a wealth of adhesins. The comparison with available genomes of other Flavobacterium species revealed a small genome size, large differences in chromosome organization, and fewer rRNA and tRNA genes, in line with its more fastidious growth. In addition, horizontal gene transfer shaped the evolution of F. branchiophilum, as evidenced by its virulence factors, genomic islands, and CRISPR (clustered regularly interspaced short palindromic repeats) systems. Further functional analysis should help in the understanding of host-pathogen interactions and in the development of rational diagnostic tools and control strategies in fish farms.

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The alternative complex III: A different architecture using known building modules

Cited by 55 publications

References 45 publications

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon

New Insight into Microbial Iron Oxidation as Revealed by the Proteomic Profile of an Obligate Iron-Oxidizing Chemolithoautotroph

Complete Genome Sequence of the Fish Pathogen Flavobacterium branchiophilum

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