Q49775 · METH_MYCLE

Function

function

Catalyzes the transfer of a methyl group from methyl-cobalamin to homocysteine, yielding enzyme-bound cob(I)alamin and methionine. Subsequently, remethylates the cofactor using methyltetrahydrofolate (By similarity).

Miscellaneous

L-homocysteine is bound via the zinc atom.

Catalytic activity

Cofactor

Protein has several cofactor binding sites:
methylcob(III)alamin (UniProtKB | Rhea| CHEBI:28115 )

Zn2+ (UniProtKB | Rhea| CHEBI:29105 )

Note: Binds 1 zinc ion per subunit.

Pathway

Amino-acid biosynthesis; L-methionine biosynthesis via de novo pathway; L-methionine from L-homocysteine (MetH route): step 1/1.

Features

Showing features for binding site.

TypeIDPosition(s)Description
Binding site233Zn2+ (UniProtKB | ChEBI)
Binding site299Zn2+ (UniProtKB | ChEBI)
Binding site300Zn2+ (UniProtKB | ChEBI)
Binding site750-754methylcob(III)alamin (UniProtKB | ChEBI)
Binding site753Co (UniProtKB | ChEBI) of methylcob(III)alamin (UniProtKB | ChEBI); axial binding residue
Binding site798methylcob(III)alamin (UniProtKB | ChEBI)
Binding site856methylcob(III)alamin (UniProtKB | ChEBI)
Binding site954S-adenosyl-L-methionine (UniProtKB | ChEBI)
Binding site1149S-adenosyl-L-methionine (UniProtKB | ChEBI)
Binding site1203-1204S-adenosyl-L-methionine (UniProtKB | ChEBI)

GO annotations

AspectTerm
Molecular Functioncobalamin binding
Molecular Functionmethionine synthase activity
Molecular Functionzinc ion binding
Biological Processmethylation
Biological Processpteridine-containing compound metabolic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Methionine synthase
  • EC number
  • Alternative names
    • 5-methyltetrahydrofolate--homocysteine methyltransferase
    • Methionine synthase, vitamin-B12 dependent (MS)

Gene names

    • Name
      metH
    • ORF names
      B2126_C1_157, MLCB2533.04
    • Ordered locus names
      ML1307

Organism names

Accessions

  • Primary accession
    Q49775
  • Secondary accessions
    • Q9CC37
    • Q9S378

Proteomes

Organism-specific databases

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00002045331-1206Methionine synthase

Interaction

Protein-protein interaction databases

Structure

Family & Domains

Features

Showing features for domain, region, compositional bias.

TypeIDPosition(s)Description
Domain1-314Hcy-binding
Domain350-609Pterin-binding
Domain642-735B12-binding N-terminal
Domain740-877B12-binding
Region873-925Disordered
Compositional bias885-924Basic and acidic residues
Domain907-1206AdoMet activation

Domain

Modular enzyme with four functionally distinct domains. The isolated Hcy-binding domain catalyzes methyl transfer from free methylcobalamin to homocysteine. The Hcy-binding domain in association with the pterin-binding domain catalyzes the methylation of cob(I)alamin by methyltetrahydrofolate and the methylation of homocysteine. The B12-binding domain binds the cofactor. The AdoMet activation domain binds S-adenosyl-L-methionine. Under aerobic conditions cob(I)alamin can be converted to inactive cob(II)alamin. Reductive methylation by S-adenosyl-L-methionine and flavodoxin regenerates methylcobalamin (By similarity).

Sequence similarities

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    1,206
  • Mass (Da)
    132,392
  • Last updated
    2001-04-27 v3
  • Checksum
    7786CE5307D7CA86
MRVTAANQHQYDTDLLETLAQRVMVGDGAMGTQLQDAELTLDDFRGLEGCNEILNETRPDVLETIHRRYFEAGADLVETNTFGCNLSNLGDYDIADKIRDLSQRGTVIARRVADELTTPDHKRYVLGSMGPGTKLPTLGHTEYRVVRDAYTESALGMLDGGADAVLVETCQDLLQLKAAVLGSRRAMTQAGRHIPVFVHVTVETTGTMLLGSEIGAALAAVEPLGVDMIGLNCATGPAEMSEHLRHLSKHARIPVSVMPNAGLPVLGAKGAEYPLQPDELAEALAGFIAEFGLSLVGGCCGTTPDHIREVAAAVARCNDGTVPRGERHVTYEPSVSSLYTAIPFAQKPSVLMIGERTNANGSKVFREAMIAEDYQKCLDIAKDQTRGGAHLLDLCVDYVGRNGVADMKALAGRLATVSTLPIMLDSTEIPVLQAGLEHLGGRCVINSVNYEDGDGPESRFVKTMELVAEHGAAVVALTIDEQGQARTVEKKVEVAERLINDITSNWGVDKSAILIDCLTFTIATGQEESRKDGIETIDAIRELKKRHPAVQTTLGLSNISFGLNPSARQVLNSVFLHECQEAGLDSAIVHASKILPINRIPEEQRQAALDLVYDRRREGYDPLQKLMWLFKGVSSPSSKETREAELAKLPLFDRLAQRIVDGERNGLDVDLDEAMTQKPPLAIINENLLDGMKTVGELFGSGQMQLPFVLQSAEVMKAAVAYLEPHMEKSDCDFGKGLAKGRIVLATVKGDVHDIGKNLVDIILSNNGYEVVNLGIKQPITNILEVAEDKSADVVGMSGLLVKSTVIMKENLEEMNTRGVAEKFPVLLGGAALTRSYVENDLAEVYEGEVHYARDAFEGLKLMDTIMSAKRGEALAPGSPESLAAEADRNKETERKARHERSKRIAVQRKAAEEPVEVPERSDVPSDVEVPAPPFWGSRIIKGLAVADYTGFLDERALFLGQWGLRGVRGGAGPSYEDLVQTEGRPRLRYWLDRLSTYGVLAYAAVVYGYFPAVSEDNDIVVLAEPRPDAEQRYRFTFPRQQRGRFLCIADFIRSRDLATERSEVDVLPFQLVTMGQPIADFVGELFVSNSYRDYLEVHGIGVQLTEALAEYWHRRIREELKFSGNRTMSADDPEAVEDYFKLGYRGARFAFGYGACPDLEDRIKMMELLQPERIGVTISEELQLHPEQSTDAFVLHHPAAKYFNV

Sequence caution

The sequence AAA17182.1 differs from that shown. Reason: Frameshift
The sequence CAA22918.1 differs from that shown. Reason: Erroneous initiation

Features

Showing features for compositional bias.

TypeIDPosition(s)Description
Compositional bias885-924Basic and acidic residues

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
U00017
EMBL· GenBank· DDBJ
AAA17182.1
EMBL· GenBank· DDBJ
Genomic DNA Frameshift
AL035310
EMBL· GenBank· DDBJ
CAA22918.1
EMBL· GenBank· DDBJ
Genomic DNA Different initiation
AL583921
EMBL· GenBank· DDBJ
CAC31688.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. Our staff consists of biologists and biochemists that are not trained to give medical advice.
We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.
FeedbackHelp