1.8.98.5: H2:CoB-CoM heterodisulfide,ferredoxin reductase
This is an abbreviated version!
For detailed information about H2:CoB-CoM heterodisulfide,ferredoxin reductase, go to the full flat file.
Word Map on EC 1.8.98.5
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1.8.98.5
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methanococcus
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methanogenic
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hydrogenases
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archaea
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nickel
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epr
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voltae
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sulfur
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methanosarcina
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energy-conserving
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ni
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hyperfine
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methanobacterium
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selenocysteine
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f420-reducing
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fad
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heterolytic
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methane
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selenium-containing
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barkeri
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illumination
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selenium
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thermoautotrophicum
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com-s-s-cob
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methanothermobacter
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hydrogenotrophic
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non-heme
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marburgensis
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acid-labile
- 1.8.98.5
- methanococcus
-
methanogenic
- hydrogenases
- archaea
- nickel
- epr
- voltae
- sulfur
- methanosarcina
-
energy-conserving
- ni
-
hyperfine
-
methanobacterium
- selenocysteine
-
f420-reducing
- fad
-
heterolytic
- methane
-
selenium-containing
- barkeri
- illumination
- selenium
- thermoautotrophicum
- com-s-s-cob
-
methanothermobacter
-
hydrogenotrophic
-
non-heme
- marburgensis
-
acid-labile
Reaction
2 reduced ferredoxin [iron-sulfur] cluster + + + 2 H+ = 2 H2 + 2 oxidized ferredoxin [iron-sulfur] cluster +
Synonyms
CoB-CoM heterodisulfide reductase, F420-non-reducing hydrogenase, H2-driven FBEB, H2: CoM-S-S-CoB oxidoreductase, H2: heterodisulfide oxidoreductase complex, HdrA, hdrA1B1C1, HdrABC, HdrABC-MvhAGD, HdrB, HdrC, HdrDE, HdrDE-VhoGAC, heterodisulfide reductase, heterodisulfide reductase complex, hydrogenase, More, Mvh, MvhA, MvhADG, MvhADG/HdrABC, MvhD, MvhG, VhoGAC, Vhu
ECTree
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General Information
General Information on EC 1.8.98.5 - H2:CoB-CoM heterodisulfide,ferredoxin reductase
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evolution
metabolism
physiological function
additional information
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general architecture and occurrence of HdrA(BC)-containing complexes, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
evolution
general architecture and occurrence of HdrA(BC)-containing complexes, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
evolution
general architecture and occurrence of HdrA(BC)-containing complexes, X-ray structure of the MvhAGD-HdrABC complex of Methanothermococcus thermolithotrophicus, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
evolution
-
general architecture and occurrence of HdrA(BC)-containing complexes, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
-
evolution
-
general architecture and occurrence of HdrA(BC)-containing complexes, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
-
evolution
-
general architecture and occurrence of HdrA(BC)-containing complexes, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
-
evolution
-
general architecture and occurrence of HdrA(BC)-containing complexes, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
-
evolution
-
general architecture and occurrence of HdrA(BC)-containing complexes, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
-
evolution
-
general architecture and occurrence of HdrA(BC)-containing complexes, overview. Overview of some biochemically and/or genetically studied HdrA(BC)-containing enzyme complexes. HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. This cysteine-rich binding motif is invariant in all HdrB components of methanogens, but also conserved in bacterial HdrB-like components where only in some cases cysteines may be substituted by serines and an aspartate. This conservation indicates that disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. The MvhD component was originally referred to as subunit of the hydrogenase component (Mvh, methyl viologen-dependent hydrogenase) in the archetypical MvhAGD-HdrABC complex. MvhD-like components may be involved in the assumed switch from one-electron to two-electron transfer. They may be dispensable, when direct hydride donors such as NAD(P)H or F420H2 directly reduce the electron-bifurcating flavin, although not in the H2:CoB-CoM heterodisulfide,ferredoxin reductase function
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generalized model for electron and proton flux during hydrogen interspecies electron transfer (HIT) and direct interspecies electron transfer (DIET) with growth on ethanol as an example, overview. H2 diffusion shuttles both electrons and protons between cells and carries both electrons and protons into the cell when cytoplasmic electron acceptors are reduced. The transcriptome reflects faster growth during HIT and possible greater importance of membrane and outer-surface proteins during DIET, but no specific upregulation of hydrogenase genes in response to growth via HIT
metabolism
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heterodisulfide reductase plays a central role in the methanogenesis cycle of Methanococcus maripaludis
metabolism
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in methanogens without cytochromes, the initial endergonic reduction of CO2 to formylmethanofuran with H2-derived electrons is coupled to the exergonic reduction of a heterodisulfide of coenzymes B and M by flavin-based electron bifurcation (FBEB). Methanococcus maripaludis employs three functional heterodisulfide reductase complexes for FBEB using hydrogen and formate. In Methanococcus maripaludis, FBEB is performed by a heterodisulfide reductase (Hdr) enzyme complex that involves hydrogenase (Vhu), although formate dehydrogenase (Fdh) has been proposed as an alternative to Vhu
metabolism
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
metabolism
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
metabolism
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase or formate dehydrogenase generates reduced ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB. F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis. Heterodisulfide reductase (HdrABC) reduces the disulfide bond in CoMS-SCoB with electrons supplied from the oxidation of 2H2 or 2HCO2H catalyzed by F420-independent hydrogenase or Fdh. Proposed role of FBEC by HdrA1B1C1 in methylotrophic pathways of methanogenesis, overview
metabolism
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase or formate dehydrogenase generates reduced ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB. F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis. Proposed role of FBEC by HdrA1B1C1 in methylotrophic pathways of methanogenesis, overview
metabolism
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase or formate dehydrogenase generates reduced ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB. F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis. Proposed role of FBEC by HdrA1B1C1 in methylotrophic pathways of methanogenesis, overview
metabolism
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase or formate dehydrogenase generates reduced ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB. F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
metabolism
the oxidation of formate is catalyzed by a membrane-bound formate dehydrogenase (FdhGHI), whereas the oxidation of H2 takes place via a membrane-bound hydrogenase (VhoGAC). Based on this, the electrons fed into the anaerobic respiratory chain by FdhGHI and VhoGAC are subsequently used by a membrane-bound heterodisulfide reductase (HdrDE) to reduce the heterodisulfide (CoM-S-S-CoB), which is the terminal electron acceptor of this system, overview. Three energy-conserving, membrane-bound electron transport systems are known in methanogens: (a) H2: CoMS-S-CoB oxidoreductase (EC 1.8.98.5), (b) coenzyme F420H2: CoMS-S-CoB oxidoreductase (EC 1.8.98.4), and (c) reduced ferredoxin:CoM-S-S-CoB oxidoreductase (EC 1.8.7.3)
metabolism
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reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
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metabolism
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reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
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metabolism
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
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metabolism
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heterodisulfide reductase plays a central role in the methanogenesis cycle of Methanococcus maripaludis
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metabolism
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in methanogens without cytochromes, the initial endergonic reduction of CO2 to formylmethanofuran with H2-derived electrons is coupled to the exergonic reduction of a heterodisulfide of coenzymes B and M by flavin-based electron bifurcation (FBEB). Methanococcus maripaludis employs three functional heterodisulfide reductase complexes for FBEB using hydrogen and formate. In Methanococcus maripaludis, FBEB is performed by a heterodisulfide reductase (Hdr) enzyme complex that involves hydrogenase (Vhu), although formate dehydrogenase (Fdh) has been proposed as an alternative to Vhu
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metabolism
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reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
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metabolism
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reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
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metabolism
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reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
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metabolism
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reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase (EC 1.12.1.2) or formate dehydrogenase generates reduces ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS-SCoB dependent on FBEB of electrons from H2 or formate, respectively. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, threefourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB, see for EC 1.8.98.4. In H2- independent acetotrophic pathways (EC 1.8.98.5), the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a NaC gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB (EC 1.8.98.4). The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis
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metabolism
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the oxidation of formate is catalyzed by a membrane-bound formate dehydrogenase (FdhGHI), whereas the oxidation of H2 takes place via a membrane-bound hydrogenase (VhoGAC). Based on this, the electrons fed into the anaerobic respiratory chain by FdhGHI and VhoGAC are subsequently used by a membrane-bound heterodisulfide reductase (HdrDE) to reduce the heterodisulfide (CoM-S-S-CoB), which is the terminal electron acceptor of this system, overview. Three energy-conserving, membrane-bound electron transport systems are known in methanogens: (a) H2: CoMS-S-CoB oxidoreductase (EC 1.8.98.5), (b) coenzyme F420H2: CoMS-S-CoB oxidoreductase (EC 1.8.98.4), and (c) reduced ferredoxin:CoM-S-S-CoB oxidoreductase (EC 1.8.7.3)
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-
HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB
physiological function
-
HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB
physiological function
HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB
physiological function
-
HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS-SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS-SCoB
physiological function
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
physiological function
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
physiological function
the energy conservation of Methanonatronarchaeum thermophilum is dependent on a respiratory chain consisting of a hydrogenase (VhoGAC, EC 1.8.98.5), a formate dehydrogenase (FdhGHI, EC 1.8.98.6), and a heterodisulfide reductase (HdrDE) that are well adapted to the harsh physicochemical conditions in the natural habitat. Methanogen Methanonatronarchaeum thermophilum is an extremely haloalkaliphilic and moderately thermophilic archaeon. A methanophenazine-like cofactor might function as an electron carrier between the hydrogenase/formate dehydrogenase and the heterodisulfide reductase. A methanophenazine-like cofactor functions as an electron carrier between the hydrogenase/formate dehydrogenase and the heterodisulfide reductase, cf. EC 1.8.98.1. The electrons fed into the anaerobic respiratory chain by FdhGHI and VhoGAC are subsequently used by a membrane-bound heterodisulfide reductase (HdrDE) to reduce the heterodisulfide (CoM-S-S-CoB), which is the terminal electron acceptor of this system
physiological function
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the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
physiological function
the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
physiological function
the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
physiological function
-
the transcriptome of Methanosarcina barkeri grown via DIET in co-culture with Geobacter metallireducens compared with its transcriptome when grown via H2 interspecies transfer (HIT) with Pelobacter carbinolicus shows that transcripts for the F420H2 dehydrogenase (Fpo) and the heterodisulfide reductase, HdrABC, are more abundant during growth on DIET. In HIT, H2 simultaneously transports both electrons and protons as the H2 diffuses between the two partners. When the H2 is oxidized in the cytoplasm with electron transfer to an electron acceptor, protons are also released and are immediately available to balance the negative charge transferred to the electron acceptor. This maintains charge balance within the cell
physiological function
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
-
physiological function
-
the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
-
physiological function
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
-
physiological function
-
the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
-
physiological function
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
-
physiological function
-
the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
-
physiological function
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
-
physiological function
-
the transcriptome of Methanosarcina barkeri grown via DIET in co-culture with Geobacter metallireducens compared with its transcriptome when grown via H2 interspecies transfer (HIT) with Pelobacter carbinolicus shows that transcripts for the F420H2 dehydrogenase (Fpo) and the heterodisulfide reductase, HdrABC, are more abundant during growth on DIET. In HIT, H2 simultaneously transports both electrons and protons as the H2 diffuses between the two partners. When the H2 is oxidized in the cytoplasm with electron transfer to an electron acceptor, protons are also released and are immediately available to balance the negative charge transferred to the electron acceptor. This maintains charge balance within the cell
-
physiological function
-
the transcriptome of Methanosarcina barkeri grown via DIET in co-culture with Geobacter metallireducens compared with its transcriptome when grown via H2 interspecies transfer (HIT) with Pelobacter carbinolicus shows that transcripts for the F420H2 dehydrogenase (Fpo) and the heterodisulfide reductase, HdrABC, are more abundant during growth on DIET. In HIT, H2 simultaneously transports both electrons and protons as the H2 diffuses between the two partners. When the H2 is oxidized in the cytoplasm with electron transfer to an electron acceptor, protons are also released and are immediately available to balance the negative charge transferred to the electron acceptor. This maintains charge balance within the cell
-
physiological function
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
-
physiological function
-
the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
-
physiological function
-
reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
-
physiological function
-
the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
-
physiological function
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reduction of the disulfide of coenzyme M and coenzyme B (CoMS-SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologues play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS-SCoM
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physiological function
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the HdrABC-MvhAGD enzyme complex is involved in methanogenesis from H2/CO2 using H2 as electron donor, ferredoxin (Fd) as low potential acceptor and CoM-S-S-CoB as high potential acceptor, it is involved in flavin-based electron bifurcation (FBEB). Structure-function analysis, overview
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physiological function
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the energy conservation of Methanonatronarchaeum thermophilum is dependent on a respiratory chain consisting of a hydrogenase (VhoGAC, EC 1.8.98.5), a formate dehydrogenase (FdhGHI, EC 1.8.98.6), and a heterodisulfide reductase (HdrDE) that are well adapted to the harsh physicochemical conditions in the natural habitat. Methanogen Methanonatronarchaeum thermophilum is an extremely haloalkaliphilic and moderately thermophilic archaeon. A methanophenazine-like cofactor might function as an electron carrier between the hydrogenase/formate dehydrogenase and the heterodisulfide reductase. A methanophenazine-like cofactor functions as an electron carrier between the hydrogenase/formate dehydrogenase and the heterodisulfide reductase, cf. EC 1.8.98.1. The electrons fed into the anaerobic respiratory chain by FdhGHI and VhoGAC are subsequently used by a membrane-bound heterodisulfide reductase (HdrDE) to reduce the heterodisulfide (CoM-S-S-CoB), which is the terminal electron acceptor of this system
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physiological function
Methanosarcina barkeri MS DSM 800
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the transcriptome of Methanosarcina barkeri grown via DIET in co-culture with Geobacter metallireducens compared with its transcriptome when grown via H2 interspecies transfer (HIT) with Pelobacter carbinolicus shows that transcripts for the F420H2 dehydrogenase (Fpo) and the heterodisulfide reductase, HdrABC, are more abundant during growth on DIET. In HIT, H2 simultaneously transports both electrons and protons as the H2 diffuses between the two partners. When the H2 is oxidized in the cytoplasm with electron transfer to an electron acceptor, protons are also released and are immediately available to balance the negative charge transferred to the electron acceptor. This maintains charge balance within the cell
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the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
additional information
the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
additional information
the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
additional information
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when grown on formate as its sole electron donor, Methanococcus maripaludis assembles three Hdr complexes employing two Vhu domains [(Vhu)2Hdr complex], two Fdh domains [(Fdh)2Hdr complex], or one Vhu and one Fdh domain forming a heterocomplex (Fdh/Vhu/Hdr complex). Protein-protein interaction/docking analysis and modeling, usage of the crystal structure of the analogous MvhHdr complex from Methanothermococcus thermolithotrophicus (PDB ID 5ODC) as template, enzyme complex structures comparisons, overview
additional information
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the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
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additional information
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the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
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additional information
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the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
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additional information
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when grown on formate as its sole electron donor, Methanococcus maripaludis assembles three Hdr complexes employing two Vhu domains [(Vhu)2Hdr complex], two Fdh domains [(Fdh)2Hdr complex], or one Vhu and one Fdh domain forming a heterocomplex (Fdh/Vhu/Hdr complex). Protein-protein interaction/docking analysis and modeling, usage of the crystal structure of the analogous MvhHdr complex from Methanothermococcus thermolithotrophicus (PDB ID 5ODC) as template, enzyme complex structures comparisons, overview
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additional information
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the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
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additional information
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the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
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additional information
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the enzyme complex HdrABC-MvhAGD is involved in Methanogenesis from H2/CO2. The electron-bifurcating HdrA subunit of HDRs is linked to three electron-input/-output modules: (i) the medium-potential electron donor module that may be connected via the MvhD adaptor, (ii) the high-potential, heterodisulfide-reducing HdrB electron acceptor module linked via the HdrC adaptor, and (iii) a low-potential electron acceptor module transferring electrons to ferredoxin (Fd). HdrB-like components contain a conserved cysteine-rich motif, referred to as CCG domain that is involved in binding two unique non-cubane [4Fe-4S] clusters. They are directly involved in heterodisulfide reduction in the active site of HDRs. Disulfide intermediates other than the CoM-S-S-CoB heterodisulfide, e.g. formed by proteinogenic cysteine residues, may also be involved in catalysis of HdrA(BC) enzymes from non-methanogens. They may transfer electrons further to an additional oxidoreductase module. Architecture and function of HdrA(BC)-containing enzyme complexes, overview
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