SMART: Pfam domain MCR

MCR_D

PFAM accession number:	PF02505
Interpro abstract (IPR003901):	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 ( EC 2.8.4.1 ), the final step in methane biosynthesis. This reaction proceeds under anaerobic conditions by methanogenic Archaea [ (PUBMED:16260307) ], 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 [ (PUBMED:11491299) ]. 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 [ (PUBMED:9367957) (PUBMED:16234924) ]. Genes encoding the beta (mcrB) and gamma (mcrG) subunits of MCR are separated by two open reading frames coding for two proteins C and D [ (PUBMED:3170483) (PUBMED:8863453) ]. The function of proteins C and D is unknown. This entry represents protein D.
GO process:	methanogenesis (GO:0015948)

PFAM accession number:

PF02505

Interpro abstract (IPR003901):

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 ( EC 2.8.4.1 ), the final step in methane biosynthesis. This reaction proceeds under anaerobic conditions by methanogenic Archaea [ (PUBMED:16260307) ], 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 [ (PUBMED:11491299) ].

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 [ (PUBMED:9367957) (PUBMED:16234924) ].

Genes encoding the beta (mcrB) and gamma (mcrG) subunits of MCR are separated by two open reading frames coding for two proteins C and D [ (PUBMED:3170483) (PUBMED:8863453) ]. The function of proteins C and D is unknown. This entry represents protein D.

GO process:

methanogenesis (GO:0015948)

This is a PFAM domain. For full annotation and more information, please see the PFAM entry MCR_D