Thiol : fumarate reductase (Tfr) from <i>Methanobacterium thermoautotrophicum</i>

Heim, Steffen; Künkel, Andreas; Thauer, Rudolf K.; Hedderich, Reiner

doi:10.1046/j.1432-1327.1998.2530292.x

Cited by 50 publications

(43 citation statements)

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“…The three additives have in common that they generate CoM-S-S-CoB. Methyl-coenzyme M generates CoM-S-S-CoB via methyl-coenzyme M reductase; fumarate via coenzyme M-and coenzyme B-dependent fumarate reductase (35); and serine via serine hydroxymethyltransferase (36), methylenetetrahydromethanopterin reductase, methyltetrahydromethanopterin:coenzyme M methyltransferase, and methyl-coenzyme M reductase. The CoM-S-S-CoB generated thus triggers the reduction of Fd with H 2 that is required as an electron donor in the initial step of methanogenesis from CO 2 .…”

Section: Discussionmentioning

confidence: 99%

Coupling of ferredoxin and heterodisulfide reduction via electron bifurcation in hydrogenotrophic methanogenic archaea

Kaster

Moll

Parey

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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In methanogenic archaea growing on H 2 and CO 2 the first step in methanogenesis is the ferredoxin-dependent endergonic reduction of CO 2 with H 2 to formylmethanofuran and the last step is the exergonic reduction of the heterodisulfide CoM-S-S-CoB with H 2 to coenzyme M (CoM-SH) and coenzyme B (CoB-SH). We recently proposed that in hydrogenotrophic methanogens the two reactions are energetically coupled via the cytoplasmic MvhADG/HdrABC complex. It is reported here that the purified complex from Methanothermobacter marburgensis catalyzes the CoM-S-S-CoB-dependent reduction of ferredoxin with H 2 . Per mole CoM-S-S-CoB added, 1 mol of ferredoxin (Fd) was reduced, indicating an electron bifurcation coupling mechanism: This stoichiometry of coupling is consistent with an ATP gain per mole methane from 4 H 2 and CO 2 of near 0.5 deduced from an H 2 -threshold concentration of 8 Pa and a growth yield of up to 3 g/mol methane.

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Section: Discussionmentioning

confidence: 99%

Coupling of ferredoxin and heterodisulfide reduction via electron bifurcation in hydrogenotrophic methanogenic archaea

Kaster

Moll

Parey

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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345

358

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“…In addition to MCR interaction, CoM is involved in a number of other enzymatic processes in methanogenic archaea. For example, most methanogens contain thio:fumarate reductase, which catalyzes the reduction of fumarate, with CoM and CoB as electron donors (8,30). Similarly, many methanogens contain a heterodisulfide reductase that catalyzes the reduction of CoM-S-S-CoB, a product formed through the reduction of fumarate and the reduction of methyl-CoM during methanogenesis (29).…”

Section: Com In Methanogenesismentioning

confidence: 99%

Getting a Handle on the Role of Coenzyme M in Alkene Metabolism

Krishnakumar

Sliwa

Endrizzi

et al. 2008

Microbiol Mol Biol Rev

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SUMMARY Coenzyme M (2-mercaptoethanesulfonate; CoM) is one of several atypical cofactors discovered in methanogenic archaea which participate in the biological reduction of CO2 to methane. Elegantly simple, CoM, so named for its role as a methyl carrier in all methanogenic archaea, is the smallest known organic cofactor. It was thought that this cofactor was used exclusively in methanogenesis until it was recently discovered that CoM is a key cofactor in the pathway of propylene metabolism in the gram-negative soil microorganism Xanthobacter autotrophicus Py2. A four-step pathway requiring CoM converts propylene and CO2 to acetoacetate, which feeds into central metabolism. In this process, CoM is used to activate and convert highly electrophilic epoxypropane, formed from propylene epoxidation, into a nucleophilic species that undergoes carboxylation. The unique properties of CoM provide a chemical handle for orienting compounds for site-specific redox chemistry and stereospecific catalysis. The three-dimensional structures of several of the enzymes in the pathway of propylene metabolism in defined states have been determined, providing significant insights into both the enzyme mechanisms and the role of CoM in this pathway. These studies provide the structural basis for understanding the efficacy of CoM as a handle to direct organic substrate transformations at the active sites of enzymes.

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“…HDR from Methanosarcina species lacks a homologue of the M. marburgensis HdrA subunit, whereas subunits HdrC and HdrB are conserved in the putative fusion protein HdrD ( Figure 1). Subunits HdrC and HdrB are also conserved in subunit TfrB of thiol:fumarate reductase (TFR) (Figure 1), an anabolic enzyme of methanogens that catalyzes the reduction of fumarate to succinate with CoM-SH plus CoB-SH as electron donors (10). HDR with highly conserved HdrB and HdrC subunits is also encoded by the genomes of uncultivated anaerobic methanotrophic archaea in which the enzyme is thought to catalyze formation of CoM-S-S-CoB from CoM-SH and CoB-SH during anaerobic methane oxidation (11).…”

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A Cysteine-Rich CCG Domain Contains a Novel [4Fe-4S] Cluster Binding Motif As Deduced from Studies with Subunit B of Heterodisulfide Reductase from Methanothermobacter marburgensis

et al. 2007

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Heterodisulfide reductase (HDR) of methanogenic archaea with its active-site [4Fe-4S] cluster catalyzes the reversible reduction of the heterodisulfide (CoM-S-S-CoB) of the methanogenic coenzyme M (CoM-SH) and coenzyme B (CoB-SH). CoM-HDR, a mechanistic-based paramagnetic intermediate generated upon half-reaction of the oxidized enzyme with CoM-SH, is a novel type of [4Fe-4S] 3+ cluster with CoM-SH as a ligand. Subunit HdrB of the Methanothermobacter marburgensis HdrABC holoenzyme contains two cysteine-rich sequence motifs (CX 31-39 CCX 35-36 CXXC), designated as CCG domain in the Pfam database and conserved in many proteins. Here we present experimental evidence that the C-terminal CCG domain of HdrB binds this unusual [4Fe-4S] cluster. HdrB was produced in Escherichia coli, and an iron-sulfur cluster was subsequently inserted by in vitro reconstitution. In the oxidized state the cluster without the substrate exhibited a rhombic EPR signal (g zyx = 2.015, 1.995, and 1.950) reminiscent of the CoM-HDR signal. 57 Fe ENDOR spectroscopy revealed that this paramagnetic species is a [4Fe-4S] cluster with 57 Fe hyperfine couplings very similar to that of CoM-HDR. CoM-33 SH resulted in a broadening of the EPR signal, and upon addition of CoM-SH the midpoint potential of the cluster was shifted to values observed for CoM-HDR, both indicating binding of CoM-SH to the cluster. Site-directed mutagenesis of all 12 cysteine residues in HdrB identified four cysteines of the C-terminal CCG domain as cluster ligands. Combined with the previous detection of CoM-HDR-like EPR signals in other CCG domain-containing proteins our data indicate a general role of the C-terminal CCG domain in coordination of this novel cluster. In addition, Zn K-edge X-ray absorption spectroscopy identified an isolated Zn site with † This work was supported by the Max Planck Society, the Deutsche Forschungsgemeinschaft, and the Fonds der Chemischen SUPPORTING INFORMATION AVAILABLESequences of oligonucleotides used in polymerase chain reactions (Table S1) and primer combinations and restriction sites used for mutations in hdrB from Methanothermobacter marburgensis (Table S2). This material is available free of charge via the Internet at http://pubs.acs.org. NIH Public Access Author ManuscriptBiochemistry. Author manuscript; available in PMC 2013 January 13. Heterodisulfide reductase (HDR 1 ) (EC 1.8.98.1) is a unique disulfide reductase with a key function in the energy metabolism of methane-producing archaea. The enzyme catalyzes the reversible reduction of the mixed disulfide (CoM-S-S-CoB) of the two methanogenic thiol coenzymes, designated coenzyme M (CoM-SH) and coenzyme B (CoB-SH). This disulfide is generated in the final step of methanogenesis (1, 2).Two types of HDRs from phylogenetically distantly related methanogens, represented by the enzymes from Methanothermobacter marburgensis (3) and from Methanosarcina barkeri and Methanosarcina thermophila (4, 5), have been identified and characterized (1,6). Neither type of enzyme belongs to t...

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Thiol : fumarate reductase (Tfr) from Methanobacterium thermoautotrophicum

Cited by 50 publications

References 1 publication

Coupling of ferredoxin and heterodisulfide reduction via electron bifurcation in hydrogenotrophic methanogenic archaea

Coupling of ferredoxin and heterodisulfide reduction via electron bifurcation in hydrogenotrophic methanogenic archaea

Getting a Handle on the Role of Coenzyme M in Alkene Metabolism

A Cysteine-Rich CCG Domain Contains a Novel [4Fe-4S] Cluster Binding Motif As Deduced from Studies with Subunit B of Heterodisulfide Reductase from Methanothermobacter marburgensis

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