MCRA_METTE
ID MCRA_METTE Reviewed; 15 AA.
AC P22948;
DT 01-AUG-1991, integrated into UniProtKB/Swiss-Prot.
DT 01-AUG-1991, sequence version 1.
DT 11-DEC-2019, entry version 53.
DE RecName: Full=Methyl-coenzyme M reductase subunit alpha;
DE EC=2.8.4.1 {ECO:0000269|PubMed:2013570};
DE AltName: Full=Coenzyme-B sulfoethylthiotransferase alpha;
DE Flags: Fragment;
OS Methanosarcina thermophila.
OC Archaea; Euryarchaeota; Stenosarchaea group; Methanomicrobia;
OC Methanosarcinales; Methanosarcinaceae; Methanosarcina.
OX NCBI_TaxID=2210;
RN [1]
RP PROTEIN SEQUENCE, FUNCTION, CATALYTIC ACTIVITY, COFACTOR,
RP BIOPHYSICOCHEMICAL PROPERTIES, SUBUNIT, AND SUBCELLULAR LOCATION.
RC STRAIN=ATCC 43570 / DSM 1825 / OCM 12 / TM-1;
RX PubMed=2013570; DOI=10.1128/jb.173.8.2481-2487.1991;
RA Jablonski P.E., Ferry J.G.;
RT "Purification and properties of methyl coenzyme M methylreductase from
RT acetate-grown Methanosarcina thermophila.";
RL J. Bacteriol. 173:2481-2487(1991).
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:0000269|PubMed:2013570}.
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:0000269|PubMed:2013570};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:12533;
CC Evidence={ECO:0000305|PubMed:2013570};
CC -!- COFACTOR:
CC Name=coenzyme F430; Xref=ChEBI:CHEBI:60540;
CC Evidence={ECO:0000269|PubMed:2013570};
CC Note=Binds 1 coenzyme F430 non-covalently per MCR heterotrimeric
CC complex. Coenzyme F430 is a yellow nickel porphinoid. Methyl-coenzyme-M
CC reductase is activated when the enzyme-bound coenzyme F430 is reduced,
CC probably to the Ni(I) oxidation state. {ECO:0000269|PubMed:2013570};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=3.3 mM for methyl-coenzyme M {ECO:0000269|PubMed:2013570};
CC KM=59 uM for coenzyme B {ECO:0000269|PubMed:2013570};
CC Vmax=125 nmol/min/mg enzyme towards coenzyme B
CC {ECO:0000269|PubMed:2013570};
CC pH dependence:
CC Optimum pH is 7.0. {ECO:0000269|PubMed:2013570};
CC Temperature dependence:
CC Optimum temperature is 60 degrees Celsius.
CC {ECO:0000269|PubMed:2013570};
CC -!- PATHWAY: One-carbon metabolism; methyl-coenzyme M reduction; methane
CC from methyl-coenzyme M: step 1/1. {ECO:0000305|PubMed:2013570}.
CC -!- SUBUNIT: MCR from M.thermophila is a heterotrimer composed of an alpha,
CC a beta, and a gamma subunit. {ECO:0000269|PubMed:2013570}.
CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000305|PubMed:2013570}.
CC -!- SIMILARITY: Belongs to the methyl-coenzyme M reductase alpha subunit
CC family. {ECO:0000305}.
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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.
PE 1: Evidence at protein level;
KW Cytoplasm; Direct protein sequencing; Methanogenesis; Nickel; Transferase.
FT CHAIN 1..>15
FT /note="Methyl-coenzyme M reductase subunit alpha"
FT /id="PRO_0000147459"
FT NON_TER 15
SQ SEQUENCE 15 AA; 1686 MW; D5D59892FCA5F63C CRC64;
AADIFAKFKT SMEVK
