ID   MCRB_METVA              Reviewed;         443 AA.
AC   P07956;
DT   01-AUG-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1988, sequence version 1.
DT   03-AUG-2022, entry version 93.
DE   RecName: Full=Methyl-coenzyme M reductase subunit beta;
DE            EC=2.8.4.1 {ECO:0000250|UniProtKB:P11560};
DE   AltName: Full=Coenzyme-B sulfoethylthiotransferase beta;
GN   Name=mcrB;
OS   Methanococcus vannielii.
OC   Archaea; Euryarchaeota; Methanomada group; Methanococci; Methanococcales;
OC   Methanococcaceae; Methanococcus.
OX   NCBI_TaxID=2187;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=16593847; DOI=10.1073/pnas.84.12.3992;
RA   Cram D.S., Sherf B.A., Libby R.T., Mattaliano R.J., Ramachandran K.L.,
RA   Reeve J.N.;
RT   "Structure and expression of the genes, mcrBDCGA, which encode the subunits
RT   of component C of methyl coenzyme M reductase in Methanococcus vannielii.";
RL   Proc. Natl. Acad. Sci. U.S.A. 84:3992-3996(1987).
CC   -!- FUNCTION: Component of the methyl-coenzyme M reductase (MCR) I that
CC       catalyzes the reductive cleavage of methyl-coenzyme M (CoM-S-CH3 or 2-
CC       (methylthio)ethanesulfonate) using coenzyme B (CoB or 7-
CC       mercaptoheptanoylthreonine phosphate) as reductant which results in the
CC       production of methane and the mixed heterodisulfide of CoB and CoM
CC       (CoM-S-S-CoB). This is the final step in methanogenesis.
CC       {ECO:0000250|UniProtKB:P11560}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=coenzyme B + methyl-coenzyme M = coenzyme M-coenzyme B
CC         heterodisulfide + methane; Xref=Rhea:RHEA:12532, ChEBI:CHEBI:16183,
CC         ChEBI:CHEBI:58286, ChEBI:CHEBI:58411, ChEBI:CHEBI:58596; EC=2.8.4.1;
CC         Evidence={ECO:0000250|UniProtKB:P11560};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:12533;
CC         Evidence={ECO:0000250|UniProtKB:P11560};
CC   -!- COFACTOR:
CC       Name=coenzyme F430; Xref=ChEBI:CHEBI:60540;
CC         Evidence={ECO:0000250|UniProtKB:P11560};
CC       Note=Binds 2 coenzyme F430 non-covalently per MCR complex. Coenzyme
CC       F430 is a yellow nickel porphinoid. Methyl-coenzyme-M reductase is
CC       activated when the enzyme-bound coenzyme F430 is reduced to the Ni(I)
CC       oxidation state. {ECO:0000250|UniProtKB:P11560};
CC   -!- PATHWAY: One-carbon metabolism; methyl-coenzyme M reduction; methane
CC       from methyl-coenzyme M: step 1/1. {ECO:0000250|UniProtKB:P11560}.
CC   -!- SUBUNIT: MCR is a hexamer of two alpha, two beta, and two gamma chains,
CC       forming a dimer of heterotrimers. {ECO:0000250|UniProtKB:P11560}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250|UniProtKB:P11560}.
CC   -!- SIMILARITY: Belongs to the methyl-coenzyme M reductase beta subunit
CC       family. {ECO:0000305}.
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DR   EMBL; M16893; AAA72594.1; -; Genomic_DNA.
DR   PIR; A27793; A27793.
DR   AlphaFoldDB; P07956; -.
DR   SMR; P07956; -.
DR   UniPathway; UPA00646; UER00699.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0050524; F:coenzyme-B sulfoethylthiotransferase activity; IEA:UniProtKB-EC.
DR   GO; GO:0015948; P:methanogenesis; IEA:UniProtKB-KW.
DR   Gene3D; 1.20.840.10; -; 1.
DR   Gene3D; 3.30.70.470; -; 1.
DR   InterPro; IPR008924; Me_CoM_Rdtase_asu/bsu_C.
DR   InterPro; IPR015823; Me_CoM_Rdtase_asu_N_sub2.
DR   InterPro; IPR003179; Me_CoM_Rdtase_bsu.
DR   InterPro; IPR022679; Me_CoM_Rdtase_bsu_C.
DR   InterPro; IPR022680; Me_CoM_Rdtase_bsu_N.
DR   InterPro; IPR009024; Me_CoM_Rdtase_Fd-like_fold.
DR   Pfam; PF02241; MCR_beta; 1.
DR   Pfam; PF02783; MCR_beta_N; 1.
DR   PIRSF; PIRSF000263; Meth_CoM_rd_beta; 1.
DR   SUPFAM; SSF48081; SSF48081; 1.
DR   SUPFAM; SSF55088; SSF55088; 1.
DR   TIGRFAMs; TIGR03257; met_CoM_red_bet; 1.
PE   3: Inferred from homology;
KW   Cytoplasm; Methanogenesis; Transferase.
FT   CHAIN           1..443
FT                   /note="Methyl-coenzyme M reductase subunit beta"
FT                   /id="PRO_0000147471"
FT   BINDING         367
FT                   /ligand="coenzyme M"
FT                   /ligand_id="ChEBI:CHEBI:58319"
FT                   /evidence="ECO:0000250|UniProtKB:P11560"
FT   BINDING         369
FT                   /ligand="coenzyme B"
FT                   /ligand_id="ChEBI:CHEBI:58596"
FT                   /evidence="ECO:0000250|UniProtKB:P11560"
SQ   SEQUENCE   443 AA;  46954 MW;  7646A0D427A98517 CRC64;
     MVKYEDKISL YDAKGNLVAE NVPLEAISPL YNPTIKSMLK NIKRTVAVNL ADIENTLATG
     SIGGKGCKVP GRTLDLSVVS NAQAIADEVE KILKVSKDDD TAIKLINGGK QMAVQVPSER
     LEVAAEYSVS MLATAMALKE AIIKTFNVDM FEGSTVHASI MGNYPQVMDY AGGNIASLLG
     APSNLEGLGY ALRNIPVNHA VATTKKNMMN AIAFSSVMEQ TATFEMGDAI GSFERQHLLG
     LAYQGLNADN LVIEFIKANG KGTVGTVVQS VVERALADGV IVVDKTMGSG FNMYKPADVN
     KWNAYAAAGL VAAAAVSCGA ARAAQNIASV ILYYNDILEY ETGLPGVDYG RSMGTAVGFS
     FFSHSIYGGG GPGIFNGNHV VTRHSKGFAI PPVCAAMCAD AGTQMFSPEH TSALVGAVYS
     AFDEFREPMK YVIERALNIK DKL