scholarly journals Assessment of the Carbon Monoxide Metabolism of the Hyperthermophilic Sulfate-Reducing ArchaeonArchaeoglobus fulgidusVC-16 by Comparative Transcriptome Analyses

Archaea ◽  
2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
William P. Hocking ◽  
Irene Roalkvam ◽  
Carina Magnussen ◽  
Runar Stokke ◽  
Ida H. Steen
Keyword(s):  
Electron Acceptor ◽  
Proton Translocation ◽  
Heterodisulfide Reductase ◽  
Sulfate Reducing ◽  
Transcription Profiles ◽  
Major Mode ◽  
Energy Conserving ◽  
Acetyl Coa Pathway ◽  
Membrane Bound ◽  
Intrinsic Capacity

The hyperthermophilic, sulfate-reducing archaeon,Archaeoglobus fulgidus, utilizes CO as an energy source and it is resistant to the toxic effects of high CO concentrations. Herein, transcription profiles were obtained fromA. fulgidusduring growth with CO and sulfate or thiosulfate, or without an electron acceptor. This provided a basis for a model of the CO metabolism ofA. fulgidus. The model suggests proton translocation by “Mitchell-type” loops facilitated by Fqo catalyzing aFdred:menaquinone oxidoreductase reaction, as the major mode of energy conservation, rather than formate or H2cycling during respiratory growth. The bifunctional CODH (cdhAB-2) is predicted to play an ubiquitous role in the metabolism of CO, and a novel nitrate reductase-associated respiratory complex was induced specifically in the presence of sulfate. A potential role of this complex in relation toFdredand APS reduction is discussed. Multiple membrane-bound heterodisulfide reductase (DsrMK) could promote both energy-conserving and non-energy-conserving menaquinol oxidation. Finally, the FqoF subunit may catalyze aFdred:F420oxidoreductase reaction. In the absence of electron acceptor, downregulation of F420H2dependent steps of the acetyl-CoA pathway is linked to transient formate generation. Overall, carboxidotrophic growth seems as an intrinsic capacity ofA. fulgiduswith little need for novel resistance or respiratory complexes.

scholarly journals The role of the membrane-bound hydrogenase in the energy-conserving oxidation of molecular hydrogen by Escherichia coli

1980 ◽  
Vol 188 (2) ◽  
pp. 345-350 ◽  
Author(s):  
R W Jones
Keyword(s):  
Escherichia Coli ◽  
Electron Acceptor ◽  
Cytoplasmic Membrane ◽  
Proton Translocation ◽  
Terminal Electron Acceptor ◽  
Benzyl Viologen ◽  
Carbonyl Cyanide ◽  
Energy Conserving ◽  
Membrane Bound ◽  
Hydroxy Quinoline

H2-dependent reduction of fumarate and nitrate by spheroplasts from Escherichia coli is coupled to the translocation of protons across the cytoplasmic membrane. The leads to H+/2e- stoicheiometry (g-ions of H+ translocated divided by mol of H2 added) is approx. 2 with fumarate and approx. 4 with nitrate as electron acceptor. This proton translocation is dependent on H2 and a terminal electron acceptor and is not observed in the presence of the protonophore carbonyl cyanide m-chlorophenylhydrazone and the respiratory inhibitor 2-n-heptyl-4-hydroxyquinoline N-oxide. H2-dependent reduction of menadione and ubiquinone-1 is coupled to a protonophore-sensitive, but 2-n-heptyl-4-hydroxy-quinoline N-oxide-insensitive, proton translocation with leads to H+/2e- stoicheiometry of approx. 2. H2-dependent reduction of Benzyl Viologen (BV++) to its radical (BV+) liberates protons at the periplasmic aspect of the cytoplasmic membrane according to the reaction: H2 + 2BV++ leads to 2H+ + 2BV+. It is concluded that the effective proton translocation observed in the H2-oxidizing segment of the anaerobic respiratory chain of Escherichia coli arises as a direct and inevitable consequence of transmembranous electron transfer between protolytic reactions that are spatially separated by a membrane of low proton-permeability.

scholarly journals Energy Conservation by the H2:Heterodisulfide Oxidoreductase from Methanosarcina mazei Gö1: Identification of Two Proton-Translocating Segments

1999 ◽  
Vol 181 (13) ◽  
pp. 4076-4080 ◽  
Author(s):  
Tina Ide ◽  
Sebastian Bäumer ◽  
Uwe Deppenmeier
Keyword(s):  
Electron Transport ◽  
Atp Synthase ◽  
Cytoplasmic Membrane ◽  
Respiratory Control ◽  
Atp Synthesis ◽  
Heterodisulfide Reductase ◽  
Methanosarcina Mazei ◽  
Energy Conserving ◽  
Membrane Bound ◽  
Synthase Inhibitor

ABSTRACT The membrane-bound H2:heterodisulfide oxidoreductase system of the methanogenic archaeon Methanosarcina mazeiGö1 catalyzed the H2-dependent reduction of 2-hydroxyphenazine and the dihydro-2-hydroxyphenazine-dependent reduction of the heterodisulfide of HS-CoM and HS-CoB (CoM-S-S-CoB). Washed inverted vesicles of this organism were found to couple both processes with the transfer of protons across the cytoplasmic membrane. The maximal H+/2e− ratio was 0.9 for each reaction. The electrochemical proton gradient (ΔμH+ ) thereby generated was shown to drive ATP synthesis from ADP plus Pi, exhibiting stoichiometries of 0.25 ATP synthesized per two electrons transported for both partial reactions. ATP synthesis and the generation of ΔμH+ were abolished by the uncoupler 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF 6847). The ATP synthase inhibitorN,N′-dicyclohexylcarbodiimide did not affect H+ translocation but led to an almost complete inhibition of ATP synthesis and decreased the electron transport rates. The latter effect was relieved by the addition of SF 6847. Thus, the energy-conserving systems showed a stringent coupling which resembles the phenomenon of respiratory control. The results indicate that two different proton-translocating segments are present in the H2:heterodisulfide oxidoreductase system; the first involves the 2-hydroxyphenazine-dependent hydrogenase, and the second involves the heterodisulfide reductase.

scholarly journals Respiration and Growth of Shewanella oneidensis MR-1 Using Vanadate as the Sole Electron Acceptor

2005 ◽  
Vol 187 (10) ◽  
pp. 3293-3301 ◽  
Author(s):  
Wesley Carpentier ◽  
Lina De Smet ◽  
Jozef Van Beeumen ◽  
Ann Brigé
Keyword(s):  
Electron Acceptor ◽  
Manganese Oxides ◽  
Proton Translocation ◽  
Shewanella Oneidensis ◽  
Anaerobic Respiration ◽  
Difference Spectra ◽  
Free Living ◽  
E Coli ◽  
Membrane Bound ◽  
Iron And Manganese

ABSTRACT Shewanella oneidensis MR-1 is a free-living gram-negative γ-proteobacterium that is able to use a large number of oxidizing molecules, including fumarate, nitrate, dimethyl sulfoxide, trimethylamine N-oxide, nitrite, and insoluble iron and manganese oxides, to drive anaerobic respiration. Here we show that S. oneidensis MR-1 is able to grow on vanadate as the sole electron acceptor. Oxidant pulse experiments demonstrated that proton translocation across the cytoplasmic membrane occurs during vanadate reduction. Proton translocation is abolished in the presence of protonophores and the inhibitors 2-heptyl-4-hydroxyquinoline N-oxide and antimycin A. Redox difference spectra indicated the involvement of membrane-bound menaquinone and cytochromes c, which was confirmed by transposon mutagenesis and screening for a vanadate reduction-deficient phenotype. Two mutants which are deficient in menaquinone synthesis were isolated. Another mutant with disruption in the cytochrome c maturation gene ccmA was unable to produce any cytochrome c and to grow on vanadate. This phenotype could be restored by complementation with the pEC86 plasmid expressing ccm genes from Escherichia coli. To our knowledge, this is the first report of E. coli ccm genes being functional in another organism. Analysis of an mtrB-deficient mutant confirmed the results of a previous paper indicating that OmcB may function as a vanadate reductase or may be part of a vanadate reductase complex.

The influence of potassium dichromate on dissimilatory reduction of sulfate and nitrate ions by bacteria Desulfovibrio sp.

2017 ◽  
Vol 28 (1-2) ◽  
pp. 84-95
Author(s):  
O. M. Moroz ◽  
S. O. Hnatush ◽  
Ch. I. Bohoslavets ◽  
T. M. Hrytsun’ ◽  
B. M. Borsukevych
Keyword(s):  
Electron Acceptor ◽  
Potassium Dichromate ◽  
Anaerobic Respiration ◽  
Sulfate Reducing Bacteria ◽  
Negative Influence ◽  
Electron Acceptors ◽  
Metal Compounds ◽  
Nitrate Ions ◽  
Sulfate Reducing ◽  
Reducing Bacteria

Sulfate reducing bacteria, capable to reductive transformation of different nature pollutants, used in biotechnologies of purification of sewage, contaminated by carbon, sulfur, nitrogen and metal compounds. H2S formed by them sediment metals to form of insoluble sulfides. Number of metals can be used by these microorganisms as electron acceptors during anaerobic respiration. Because under the influence of metal compounds observed slowing of bacteria metabolism, selection isolated from technologically modified ecotops resistant to pollutions strains is important task to create a new biotechnologies of purification. That’s why the purpose of this work was to study the influence of potassium dichromate, present in medium, on reduction of sulfate and nitrate ions by sulfate reducing bacteria Desulfovibrio desulfuricans IMV K-6, Desulfovibrio sp. Yav-6 and Desulfovibrio sp. Yav-8, isolated from Yavorivske Lake, to estimate the efficiency of possible usage of these bacteria in technologies of complex purification of environment from dangerous pollutants. Bacteria were cultivated in modified Kravtsov-Sorokin medium without SO42- and FeCl2×4H2O for 10 days. To study the influence of K2Cr2O7 on usage by bacteria SO42- or NO3- cells were seeded to media with Na2SO4×10H2O or NaNO3 and K2Cr2O7 at concentrations of 1.74 mM for total content of electron acceptors in medium 3.47 mM (concentration of SO42- in medium of standard composition). Cells were also seeded to media with 3.47 mM Na2SO4×10H2O, NaNO3 or K2Cr2O7 to investigate their growth in media with SO42-, NO3- or Cr2O72- as sole electron acceptor (control). Biomass was determined by turbidymetric method, content of sulfate, nitrate, dichromate, chromium (III) ions, hydrogen sulfide or ammonia ions in cultural liquid – by spectrophotometric method. It was found that K2Cr2O7 inhibits growth (2.2 and 1.3 times) and level of reduction by bacteria sulfate or nitrate ions (4.2 and 3.0 times, respectively) at simultaneous addition into cultivation medium of 1.74 mM SO42- or NO3- and 1.74 mM Cr2O72-, compared with growth and level of reduction of sulfate or nitrate ions in medium only with SO42- or NO3- as sole electron acceptor. Revealed that during cultivation of bacteria in presence of equimolar amount of SO42- or NO3- and Cr2O72-, last used by bacteria faster, content of Cr3+ during whole period of bacteria cultivation exceeded content H2S or NH4+. K2Cr2O7 in medium has most negative influence on dissimilatory reduction by bacteria SO42- than NO3-, since level of nitrate ions reduction by cells in medium with NO3- and Cr2O72- was a half times higher than level of sulfate ions reduction by it in medium with SO42- and Cr2O72-. The ability of bacteria Desulfovibrio sp. to priority reduction of Cr2O72- and after their exhaustion − NO3- and SO42- in the processes of anaerobic respiration can be used in technologies of complex purification of environment from toxic compounds.

scholarly journals Mutation of a single residue in the ba3 oxidase specifically impairs protonation of the pump site

2015 ◽  
Vol 112 (11) ◽  
pp. 3397-3402 ◽  
Author(s):  
Christoph von Ballmoos ◽  
Nathalie Gonska ◽  
Peter Lachmann ◽  
Robert B. Gennis ◽  
Pia Ädelroth ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Time Constant ◽  
Thermus Thermophilus ◽  
Proton Translocation ◽  
Proton Pumping ◽  
Wild Type ◽  
Structural Variant ◽  
In The Wild ◽  
Membrane Bound ◽  
Proton Uptake

The ba3-type cytochrome c oxidase from Thermus thermophilus is a membrane-bound protein complex that couples electron transfer to O2 to proton translocation across the membrane. To elucidate the mechanism of the redox-driven proton pumping, we investigated the kinetics of electron and proton transfer in a structural variant of the ba3 oxidase where a putative “pump site” was modified by replacement of Asp372 by Ile. In this structural variant, proton pumping was uncoupled from internal electron transfer and O2 reduction. The results from our studies show that proton uptake to the pump site (time constant ∼65 μs in the wild-type cytochrome c oxidase) was impaired in the Asp372Ile variant. Furthermore, a reaction step that in the wild-type cytochrome c oxidase is linked to simultaneous proton uptake and release with a time constant of ∼1.2 ms was slowed to ∼8.4 ms, and in Asp372Ile was only associated with proton uptake to the catalytic site. These data identify reaction steps that are associated with protonation and deprotonation of the pump site, and point to the area around Asp372 as the location of this site in the ba3 cytochrome c oxidase.

scholarly journals Global transcriptomics analysis of the Desulfovibrio vulgaris change from syntrophic growth with Methanosarcina barkeri to sulfidogenic metabolism

Microbiology ◽  
2010 ◽  
Vol 156 (9) ◽  
pp. 2746-2756 ◽  
Author(s):  
Caroline M. Plugge ◽  
Johannes C. M. Scholten ◽  
David E. Culley ◽  
Lei Nie ◽  
Fred J. Brockman ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Cell Envelope ◽  
Methanosarcina Barkeri ◽  
Desulfovibrio Vulgaris ◽  
Dual Culture ◽  
Dual Cultures ◽  
Genes Encoding ◽  
Energy Conserving ◽  
Membrane Bound ◽  
Functional Analyses

Desulfovibrio vulgaris is a metabolically flexible micro-organism. It can use sulfate as an electron acceptor to catabolize a variety of substrates, or in the absence of sulfate can utilize organic acids and alcohols by forming a syntrophic association with a hydrogen-scavenging partner to relieve inhibition by hydrogen. These alternative metabolic types increase the chance of survival for D. vulgaris in environments where one of the potential external electron acceptors becomes depleted. In this work, whole-genome D. vulgaris microarrays were used to determine relative transcript levels as D. vulgaris shifted its metabolism from syntrophic in a lactate-oxidizing dual-culture with Methanosarcina barkeri to a sulfidogenic metabolism. Syntrophic dual-cultures were grown in two independent chemostats and perturbation was introduced after six volume changes with the addition of sulfate. The results showed that 132 genes were differentially expressed in D. vulgaris 2 h after addition of sulfate. Functional analyses suggested that genes involved in cell envelope and energy metabolism were the most regulated when comparing syntrophic and sulfidogenic metabolism. Upregulation was observed for genes encoding ATPase and the membrane-integrated energy-conserving hydrogenase (Ech) when cells shifted to a sulfidogenic metabolism. A five-gene cluster encoding several lipoproteins and membrane-bound proteins was downregulated when cells were shifted to a sulfidogenic metabolism. Interestingly, this gene cluster has orthologues found only in another syntrophic bacterium, Syntrophobacter fumaroxidans, and four recently sequenced Desulfovibrio strains. This study also identified several novel c-type cytochrome-encoding genes, which may be involved in the sulfidogenic metabolism.

scholarly journals Preferential Reduction of the Thermodynamically Less Favorable Electron Acceptor, Sulfate, by a Nitrate-Reducing Strain of the Sulfate-Reducing Bacterium Desulfovibrio desulfuricans 27774

2008 ◽  
Vol 191 (3) ◽  
pp. 882-889 ◽  
Author(s):  
Angeliki Marietou ◽  
Lesley Griffiths ◽  
Jeff Cole
Keyword(s):  
Transcription Start Site ◽  
Electron Acceptor ◽  
Nitrate Reduction ◽  
Desulfovibrio Desulfuricans ◽  
Start Codon ◽  
Start Site ◽  
Transcription Start ◽  
Sulfate Reducing ◽  
Reverse Transcription Pcr ◽  
Nitrate Induction

ABSTRACT Desulfovibrio desulfuricans strain 27774 is one of a relative small group of sulfate-reducing bacteria that can also grow with nitrate as an alternative electron acceptor, but how nitrate reduction is regulated in any sulfate-reducing bacterium is controversial. Strain 27774 grew more rapidly and to higher yields of biomass with nitrate than with sulfate or nitrite as the only electron acceptor. In the presence of both sulfate and nitrate, sulfate was used preferentially, even when cultures were continuously gassed with nitrogen and carbon dioxide to prevent sulfide inhibition of nitrate reduction. The napC transcription start site was identified 112 bases upstream of the first base of the translation start codon. Transcripts initiated at the napC promoter that were extended across the napM-napA boundary were detected by reverse transcription-PCR, confirming that the six nap genes can be cotranscribed as a single operon. Real-time PCR experiments confirmed that nap operon expression is regulated at the level of mRNA transcription by at least two mechanisms: nitrate induction and sulfate repression. We speculate that three almost perfect inverted-repeat sequences located upstream of the transcription start site might be binding sites for one or more proteins of the CRP/FNR family of transcription factors that mediate nitrate induction and sulfate repression of nitrate reduction by D. desulfuricans.

scholarly journals The A1Ao ATPase fromMethanosarcina mazei: Cloning of the 5′ End of theaha Operon Encoding the Membrane Domain and Expression of the Proteolipid in a Membrane-Bound Form in Escherichia coli

1998 ◽  
Vol 180 (13) ◽  
pp. 3448-3452 ◽  
Author(s):  
Claudia Ruppert ◽  
Sönke Wimmers ◽  
Thorsten Lemker ◽  
Volker Müller
Keyword(s):  
Escherichia Coli ◽  
Proton Translocation ◽  
Promoter Sequence ◽  
Membrane Domain ◽  
Sequence Comparisons ◽  
Hydrophobic Domain ◽  
E Coli ◽  
Methanosarcina Mazei ◽  
Membrane Bound ◽  
And Function

ABSTRACT Three additional ATPase genes, clustered in the orderahaH, ahaI, and ahaK, were found upstream of the previously characterized genes ahaECFABDGcoding for the archaeal A1Ao ATPase fromMethanosarcina mazei. ahaH, the first gene in the cluster, is preceded by a conserved promoter sequence. Northern blot analysis revealed that the clusters ahaHIK andahaECFABDG are transcribed as one message. AhaH is a hydrophilic polypeptide and is similar to peptides of previously unassigned function encoded by genes preceding postulated ATPase genes in Methanobacterium thermoautotrophicum andMethanococcus jannaschii. AhaI has a two-domain structure with a hydrophilic domain of 39 kDa and a hydrophobic domain with seven predicted transmembrane α helices. It is similar to the 100-kDa polypeptide of V1Vo ATPases and is therefore suggested to participate in proton transport. AhaK is a hydrophobic polypeptide with two predicted transmembrane α helices and, on the basis of sequence comparisons and immunological studies, is identified as the proteolipid, a polypeptide which is essential for proton translocation. However, it is only one-half and one-third the size of the proteolipids from M. thermoautotrophicum and M. jannaschii, respectively. ahaK is expressed inEscherichia coli, and it is incorporated into the cytoplasmic membrane despite the different chemical natures of lipids from archaea and bacteria. This is the first report on the expression and incorporation into E. coli lipids of a membrane integral enzyme from a methanogens, which will facilitate analysis of the structure and function of the membrane domain of the methanoarchaeal ATPase.

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