Protein Domain : Methyl-coenzyme M reductase, protein D IPR003901

Type	Family
Description	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 ( ), the final step in methane biosynthesis. This reaction proceeds under anaerobic conditions by methanogenic Archaea [ ], 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 [].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 [ , ]. 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 [ , ]. The function of proteins C and D is unknown. This entry represents protein D.
Short Name	Me_CoM_Rdtase_D