G3DSA:1.20.840.10

Methyl-coenzyme M reductase, alpha/beta subunit, C-terminal

CATH-Gene3D entry
Member databaseCATH-Gene3D
CATH-Gene3D typehomologous superfamily

Description
Imported from IPR008924

Methyl-coenzyme M reductase (MCR) catalyses the reduction of methyl-coenzyme M (CH3-SCoM) and coenzyme B (HS-CoB) to methane and the corresponding heterosulphide CoM-S-S-CoB (
2.8.4.1
), the final step in methane biosynthesis. This reaction proceeds under anaerobic conditions by methanogenic Archaea
[3]
, and requires a nickel-porphinoid prosthetic group, coenzyme F430, which is in the EPR-detectable Ni(I) oxidation state in the active enzyme. Studies on a catalytically inactive enzyme aerobically co-crystallized with coenzyme M displayed a fully occupied coenzyme M-binding site with no alternate conformations. The binding of coenzyme M appears to induce specific conformational changes that suggests a molecular mechanism by which the enzyme ensures that methyl-coenzyme M enters the substrate channel prior to coenzyme B, as required by the active-site geometry
[1]
.

MCR is a hexamer composed of 2 alpha, 2 beta, and 2 gamma subunits with two identical nickel porphinoid active sites, which form two long active site channels with F430 embedded at the bottom
[2, 4]
.

This superfamily represents the C-terminal domain of the alpha and beta subunits, which share a common structure. The C-terminal domain is a multi-helical bundle and contains a buried central helix.

References
Imported from IPR008924

1.On the mechanism of biological methane formation: structural evidence for conformational changes in methyl-coenzyme M reductase upon substrate binding. Grabarse W, Mahlert F, Duin EC, Goubeaud M, Shima S, Thauer RK, Lamzin V, Ermler U. J. Mol. Biol. 309, 315-30, (2001). View articlePMID: 11491299

2.Crystal structure of methyl-coenzyme M reductase: the key enzyme of biological methane formation. Ermler U, Grabarse W, Shima S, Goubeaud M, Thauer RK. Science 278, 1457-62, (1997). View articlePMID: 9367957

3.Methyl-coenzyme M reductase genes: unique functional markers for methanogenic and anaerobic methane-oxidizing Archaea. Friedrich MW. Meth. Enzymol. 397, 428-42, (2005). View articlePMID: 16260307

4.On the mechanism of methyl-coenzyme M reductase. Ermler U. 3451-8, (2005). View articlePMID: 16234924

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