The alternative complex III from <i>Rhodothermus marinus</i> – A prototype of a new family of quinol:electron acceptor oxidoreductases

Pereira, Manuela M.; Refojo, Patrícia N.; Hreggviðsson, Guðmundur Ó.; Hjörleifsdóttir, Sigríður; Teixeira, Miguel

doi:10.1016/j.febslet.2007.09.008

Cited by 56 publications

(49 citation statements)

References 39 publications

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“…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). Despite this, it has been proposed that ActB in these organisms does not contain a molybdopterin cofactor (36,37). Interestingly, in FeOB, actB is split into two genes, actB1 and actB2.…”

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

125

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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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

125

150

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“…The sigma factors include an RpoD ( 70 ) homolog, an RpoN ( 54 ) homolog, and 27 sigma factors belonging to the ECF subfamily. F. johnsoniae RpoD is similar in size (32.7 kDa) and sequence to other bacteroidete RpoD proteins and is much smaller than E. coli 70 . Like the other bacteroidete RpoD proteins, F. johnsoniae RpoD lacks regions found in most nonbacteroidete RpoD proteins, such as Nterminal region 1.1 and the segment between regions 1.2 and 2.1 (92).…”

mentioning

confidence: 94%

“…Instead, F. johnsoniae has genes encoding components of an alternative complex III that is thought to function as a menaquinol:cytochrome c oxidoreductase. The components of this complex were recently recognized in the distantly related bacteroidete R. marinus and in the photosynthetic bacterium Chloroflexus aurantiacus (70,99). Involvement of menaquinones and replacement of the bc 1 complex with the novel menaquinol oxidoreductase appear to be universal among aerobic bacteroidetes for which genome sequence data are available, including F. johnsoniae, F. psychrophilum, Gramella forsetii, C. hutchinsonii, and R. marinus.…”

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confidence: 99%

Novel Features of the Polysaccharide-Digesting Gliding Bacterium Flavobacterium johnsoniae as Revealed by Genome Sequence Analysis

McBride

Xie

Martens

et al. 2009

Appl Environ Microbiol

215

253

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The 6.10-Mb genome sequence of the aerobic chitin-digesting gliding bacterium Flavobacterium johnsoniae (phylum Bacteroidetes) is presented. F. johnsoniae is a model organism for studies of bacteroidete gliding motility, gene regulation, and biochemistry. The mechanism of F. johnsoniae gliding is novel, and genome analysis confirms that it does not involve well-studied motility organelles, such as flagella or type IV pili. The motility machinery is composed of Gld proteins in the cell envelope that are thought to comprise the "motor" and SprB, which is thought to function as a cell surface adhesin that is propelled by the motor. Analysis of the genome identified genes related to sprB that may encode alternative adhesins used for movement over different surfaces. Comparative genome analysis revealed that some of the gld and spr genes are found in nongliding bacteroidetes and may encode components of a novel protein secretion system. F. johnsoniae digests proteins, and 125 predicted peptidases were identified. F. johnsoniae also digests numerous polysaccharides, and 138 glycoside hydrolases, 9 polysaccharide lyases, and 17 carbohydrate esterases were predicted. The unexpected ability of F. johnsoniae to digest hemicelluloses, such as xylans, mannans, and xyloglucans, was predicted based on the genome analysis and confirmed experimentally. Numerous predicted cell surface proteins related to Bacteroides thetaiotaomicron SusC and SusD, which are likely involved in binding of oligosaccharides and transport across the outer membrane, were also identified. Genes required for synthesis of the novel outer membrane flexirubin pigments were identified by a combination of genome analysis and genetic experiments. Genes predicted to encode components of a multienzyme nonribosomal peptide synthetase were identified, as were novel aspects of gene regulation. The availability of techniques for genetic manipulation allows rapid exploration of the features identified for the polysaccharide-digesting gliding bacteroidete F. johnsoniae.

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“…An example of a novel BRC has recently been described that is a functional substitute for the bc 1 complex, or complex III (7)(8)(9). This complex, named alternative complex III (ACIII), is found in many groups of bacteria whose genome lacks a complex III but includes heme-copper oxygen reductases that receive electrons from soluble periplasmic proteins (thus requiring the presence of a protein to transfer electrons from the quinone pool to these proteins).…”

mentioning

confidence: 99%

The Qrc Membrane Complex, Related to the Alternative Complex III, Is a Menaquinone Reductase Involved in Sulfate Respiration

Venceslau¹,

Lino

Pereira

2010

Journal of Biological Chemistry

125

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Biological sulfate reduction is a process with high environmental significance due to its major contribution to the carbon and sulfur cycles in anaerobic environments. However, the respiratory chain of sulfate-reducing bacteria is still poorly understood. Here we describe a new respiratory complex that was isolated as a major protein present in the membranes of Desulfovibrio vulgaris Hildenborough. The complex, which was named Qrc, is the first representative of a new family of redox complexes. It has three subunits related to the complex iron-sulfur molybdoenzyme family and a multiheme cytochrome c and binds six hemes c, one Respiratory chains rely on membrane-bound protein complexes to perform a stepwise transduction of the free energy of redox reactions into an electrochemical potential difference across the membrane that drives the synthesis of ATP. In aerobic eukaryotic organisms, a fixed and mostly linear respiratory chain is present, in contrast to bacteria and archaea whose flexible and usually highly branched respiratory chains reflect their ability to use an array of different electrons donors and acceptors (1). This flexibility enables prokaryotes to explore virtually every possible energy source and oxidant pairs that can provide energy to sustain life and, thus, colonize multiple habitats on earth, including the most extreme environments. In addition, the recycling of elements provided by bacterial energy metabolism is a crucial component for the maintenance of life in our planet (2). The study of bacterial respiratory complexes (BRCs) 3 has highlighted the diversity of mechanisms by which energy conservation can be achieved (3, 4). BRCs usually have simpler compositions than their eukaryotic counterparts and are, therefore, useful models to understand the molecular mechanisms involved in those processes. Furthermore, bacteria contain many unique BRCs whose architectures have highly modular characters, with dif-

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The alternative complex III from Rhodothermus marinus – A prototype of a new family of quinol:electron acceptor oxidoreductases

Cited by 56 publications

References 39 publications

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

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

Novel Features of the Polysaccharide-Digesting Gliding Bacterium Flavobacterium johnsoniae as Revealed by Genome Sequence Analysis

The Qrc Membrane Complex, Related to the Alternative Complex III, Is a Menaquinone Reductase Involved in Sulfate Respiration

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