CoChat
Sign Up
Cited by 177Metalloenzymes and iron-sulfur proteinsMicrobial metabolism and enzyme functionMicrobial Fuel Cells and Bioremediation

Electron Bifurcation Involved in the Energy Metabolism of the Acetogenic Bacterium Moorella thermoacetica Growing on Glucose or H 2 plus CO 2

Open access
Huang, Haiyan, Wang, Shuning, Moll, Johanna, Thauer, Rudolf K.·2012·Journal of Bacteriology
DOI 10.1128/jb.00385-12PMC PMC3393501
Open this paper in CoChat — free accountOpen PDF

Abstract

Moorella thermoacetica ferments glucose to three acetic acids. In the oxidative part of the fermentation, the hexose is converted to 2 acetic acids and 2 CO 2 molecules with the formation of 2 NADH and 2 reduced ferredoxin (Fd red 2− ) molecules. In the reductive part, 2 CO 2 molecules are reduced to acetic acid, consuming the 8 reducing equivalents generated in the oxidative part. An open question is how the two parts are electronically connected, since two of the four oxidoreductases involved in acetogenesis from CO 2 are NADP specific rather than NAD specific. We report here that the 2 NADPH molecules required for CO 2 reduction to acetic acid are generated by the reduction of 2 NADP + molecules with 1 NADH and 1 Fd red 2− catalyzed by the electron-bifurcating NADH-dependent reduced ferredoxin:NADP + oxidoreductase (NfnAB). The cytoplasmic iron-sulfur flavoprotein was heterologously produced in Escherichia coli , purified, and characterized. The purified enzyme was composed of 30-kDa (NfnA) and 50-kDa (NfnB) subunits in a 1-to-1 stoichiometry. NfnA harbors a [2Fe2S] cluster and flavin adenine dinucleotide (FAD), and NfnB harbors two [4Fe4S] clusters and FAD. M. thermoacetica contains a second electron-bifurcating enzyme. Cell extracts catalyzed the coupled reduction of NAD + and Fd with 2 H 2 molecules. The specific activity of this cytoplasmic enzyme was 3-fold higher in H 2 -CO 2 -grown cells than in glucose-grown cells. The function of this electron-bifurcating hydrogenase is not yet clear, since H 2 -CO 2 -grown cells additionally contain high specific activities of an NADP + -dependent hydrogenase that catalyzes the reduction of NADP + with H 2 . This activity is hardly detectable in glucose-grown cells.

Integrity signals

Registry

Crossref · 10.1128/jb.00385-12

Cites

74 of 74 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

We couldn’t retrieve this paper’s full text, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The formation of formyl-H4F is endergonic, requiring ATP hydrolysis, while the 5,10-methylene-H4F reductase step is highly exergonic (-57 kJ mol−1) and is suspected to be a site of energy conservation in some acetogen species.

    “Of energetic consequence, the formation of the formyl pterin formyl-H4F is endergonic, requiring ATP hydrolysis, while the 5,10-methylene-H4F reductase step is highly exergonic (–57 kJ mol−1) [73] and is suspected to be a site of energy conservation in some acetogen species [89].”

    From Early bioenergetic evolution (2013) · cites this paper as [89]

  • The cytochrome-containing acetogens such as Moorella contain menaquinone, but there is yet no obvious role for it in core metabolism.

    “The cytochrome-containing acetogens such as Moorella, in particular, come to mind in this respect, because they contain menaquinone, but there is yet no obvious role for it in core metabolism [89].”

    From Early bioenergetic evolution (2013) · cites this paper as [89]

  • Soluble confurcation processes have already been described, such as those involving multimeric hydrogenases and the NfnAB transhydrogenase.

    “Soluble confurcation processes have already been described, such as those involving multimeric hydrogenases (NADH and Fdred as electron donors for H2 production) [196] and the NfnAB transhydrogenase (NADH and Fdred as electron donors for NADP+ reduction) [89,198].”

    From Early bioenergetic evolution (2013) · cites this paper as [89]

  • Homologues of HdrABC are found in other organisms, including at least one cytochrome-containing acetogen, Moorella thermoacetica, and many proteobacterial and clostridial sulfate reducers.

    “Homologues of HdrABC are found in other organisms, including at least one cytochrome-containing acetogen, Moorella thermoacetica [89], and many proteobacterial and clostridial sulfate reducers [172].”

    From Early bioenergetic evolution (2013) · cites this paper as [89]

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Related

Authors
Huang, H., Wang, S., Moll, J., & Thauer, R. K.
Affiliations
  • Max Planck Institute for Terrestrial Microbiology (DE)
  • Shandong University (CN)
ORCID
Venue
Journal of Bacteriology
Publisher
American Society for Microbiology
Published
2012-07-15
Volume
194
Issue
14
Pages
3689-3699
ISSN
  • 0021-9193 (ISSN-L)
  • 1098-5530
DOI
10.1128/jb.00385-12
PMC
PMC3393501
OpenAlex
W2117142868
Cited by
177
References
74
Citations by year
2026: 12 · 2025: 6 · 2024: 12 · 2023: 9 · 2022: 8 · 2021: 13 · 2020: 6 · 2019: 13 · 2018: 15 · 2017: 15 · 2016: 16 · 2015: 18 · 2014: 15 · 2013: 12 · 2012: 7
FWCI
6.38
Type
journal article
Language
en
Open access
Licence
journals.asm.org/non-commercial-tdm-license (tdm)
Locations
  • Journal of Bacteriology (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • Max Planck Institute for Plasma Physics (submittedVersion)
  • MPG.PuRe (Max Planck Society) (submittedVersion)
Funders
Max-Planck-Gesellschaft
Topics
  • Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › Metalloenzymes and iron-sulfur proteins
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Microbial metabolism and enzyme function
  • Physical Sciences › Environmental Science › Environmental Engineering › Microbial Fuel Cells and Bioremediation
Keywords
electron bifurcation, Moorella thermoacetica, acetogenesis, hydrogenase, NADPH production, ferredoxin, iron-sulfur flavoprotein, glucose fermentation, energy metabolism, NADH oxidation
MeSH terms
Carbon Dioxide, Electrons, Energy Metabolism, Glucose, Hydrogen, Molecular Sequence Data, Oxidoreductases, Gene Expression Regulation, Bacterial, Gene Expression Regulation, Enzymologic, Moorella

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review