EC Number   |
General Information |
Reference |
|---|
   1.8.98.6 | metabolism |
heterodisulfide reductase plays a central role in the methanogenesis cycle of Methanococcus maripaludis. 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 |
-, 764153 |
| 1.8.98.6 | 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) |
-, 764660 |
| 1.8.98.6 | more |
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 |
-, 764153 |
| 1.8.98.6 | 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 |
-, 764660 |
