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Literature summary for 1.8.7.3 extracted from

  • Yan, Z.; Ferry, J.
    Electron bifurcation and confurcation in methanogenesis and reverse methanogenesis (2018), Front. Microbiol., 9, 1322 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 1.8.7.3

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2 reduced ferredoxin [iron-sulfur] cluster + CoB + CoM + 2 H+ Methanothermococcus thermolithotrophicus
-
 2 H2 + 2 oxidized ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB
-
 ?
2 reduced ferredoxin [iron-sulfur] cluster + CoB + CoM + 2 H+ Methanothermococcus thermolithotrophicus DSM 2095
-
 2 H2 + 2 oxidized ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB
-
 ?

Organism

Organism UniProt Comment Textmining
Methanothermococcus thermolithotrophicus A0A2D0TCB9 AND A0A2D0TCB4 AND A0A2D0TC97 CoB-CoM heterodisulfide reductase subunits A, B, and C
-
Methanothermococcus thermolithotrophicus DSM 2095 A0A2D0TCB9 AND A0A2D0TCB4 AND A0A2D0TC97 CoB-CoM heterodisulfide reductase subunits A, B, and C
-

Reaction

Reaction Comment Organism Reaction ID
2 oxidized ferredoxin [iron-sulfur] cluster + CoB + CoM = 2 reduced ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB + 2 H+ reaction mechanism, overview Methanothermococcus thermolithotrophicus
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2 reduced ferredoxin [iron-sulfur] cluster + CoB + CoM + 2 H+
-
 Methanothermococcus thermolithotrophicus 2 H2 + 2 oxidized ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB
-
 ?
2 reduced ferredoxin [iron-sulfur] cluster + CoB + CoM + 2 H+
-
 Methanothermococcus thermolithotrophicus DSM 2095 2 H2 + 2 oxidized ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB
-
 ?
additional information heterodisulfide reductase (HdrABC) reduces the disulfide bond with electrons supplied from the oxidation of 2H2 or 2HCO2H catalyzed by F420-independent hydrogenase or Fdh. The exergonic reduction of CoMS-SCoB drives the endergonic reduction of CO2 in the first step via FBEB by HdrABC Methanothermococcus thermolithotrophicus ?
-
-
additional information heterodisulfide reductase (HdrABC) reduces the disulfide bond with electrons supplied from the oxidation of 2H2 or 2HCO2H catalyzed by F420-independent hydrogenase or Fdh. The exergonic reduction of CoMS-SCoB drives the endergonic reduction of CO2 in the first step via FBEB by HdrABC Methanothermococcus thermolithotrophicus DSM 2095 ?
-
-

Synonyms

Synonyms Comment Organism
CoB-CoM heterodisulfide reductase
-
 Methanothermococcus thermolithotrophicus
HdrABC
-
 Methanothermococcus thermolithotrophicus

Cofactor

Cofactor Comment Organism Structure
Ferredoxin
-
 Methanothermococcus thermolithotrophicus

General Information

General Information Comment Organism
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 Methanothermococcus thermolithotrophicus
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 Methanothermococcus thermolithotrophicus