A0A126QFW5 · A0A126QFW5_9ENTR

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.

Caution

Lacks conserved residue(s) required for the propagation of feature annotation.

Catalytic activity

Cofactor

Protein has several cofactor binding sites:
Zn2+ (UniProtKB | Rhea| CHEBI:29105 )

methylcob(III)alamin (UniProtKB | Rhea| CHEBI:28115 )

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 site53Zn2+ (UniProtKB | ChEBI)
Binding site54Zn2+ (UniProtKB | ChEBI)
Binding site437methylcob(III)alamin (UniProtKB | ChEBI)
Binding site499-503methylcob(III)alamin (UniProtKB | ChEBI)
Binding site502Co (UniProtKB | ChEBI) of methylcob(III)alamin (UniProtKB | ChEBI); axial binding residue
Binding site547methylcob(III)alamin (UniProtKB | ChEBI)
Binding site551methylcob(III)alamin (UniProtKB | ChEBI)
Binding site603methylcob(III)alamin (UniProtKB | ChEBI)
Binding site689S-adenosyl-L-methionine (UniProtKB | ChEBI)
Binding site877S-adenosyl-L-methionine (UniProtKB | ChEBI)
Binding site932-933S-adenosyl-L-methionine (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentcytosol
Molecular Functioncobalamin binding
Molecular Functionmethionine synthase activity
Molecular Functionzinc ion binding
Biological Processhomocysteine metabolic process
Biological Processmethylation
Biological Processtetrahydrofolate metabolic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Methionine synthase
  • EC number
  • Alternative names
    • 5-methyltetrahydrofolate--homocysteine methyltransferase

Gene names

    • Name
      mthM

Organism names

  • Taxonomic identifier
  • Organism
  • Strain
    • NT18-21Contig1
  • Taxonomic lineage
    Bacteria > Pseudomonadota > Gammaproteobacteria > Enterobacterales > Enterobacteriaceae > Klebsiella/Raoultella group > Klebsiella

Accessions

  • Primary accession
    A0A126QFW5

Subcellular Location

Family & Domains

Features

Showing features for domain.

TypeIDPosition(s)Description
Domain1-68Hcy-binding
Domain99-360Pterin-binding
Domain393-487B12-binding N-terminal
Domain489-624B12-binding
Domain640-970AdoMet 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.

Sequence similarities

Belongs to the vitamin-B12 dependent methionine synthase family.

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    970
  • Mass (Da)
    107,968
  • Last updated
    2016-05-11 v1
  • Checksum
    F09925263F7CB705
MQELSRIAECYVTAHPNAGLPNAFGEYDLDADTMATQIREWAEAGFLNVVGGCCGTTPEHIAAMSRAVEGLPPRKLPELPVACRLSGLEPLNIGDDSLFVNVGERTNVTGSAKFKRLIKEEKYNEALAVARQQVESGAQIIDINMDEGMLDAEAAMVRFLNLIAGEPDIARVPIMIDSSKWDVIEKGLKCIQGKGIVNSISMKEGIEPFIQHAKKVRRYGAAVVVMAFDEVGQADTRERKIEICRRAYNILTKEVGFPPEDIIFDPNIFAVATGIEEHNNYAQDFIGACEDIKRELPHALISGGVSNVSFSFRGNDPVREAIHAVFLYYAIRNGMDMGIVNAGQLAIYDDLPAELRDAVEDVVLNRRDDGTERLLDLAEKYRGSKTDDTANAQQAEWRSWDVKKRLEYSLVKGITEFIEQDTEEARQQAERPIQVIEGPLMDGMNVVGDLFGEGKMFLPQVVKSARVMKQAVAYLEPYIEASKEKGSSNGKMVIATVKGDVHDIGKNIVGVVLQCNNYEIIDLGVMVPADKILKTAREVNADLIGLSGLITPSLDEMVNVAKEMERQGFSIPLLIGGATTSKAHTAVKIEQNYSGPTVYVQNASRTVGVVAALLSDTQHDDFVARTRKEYETVRIQHGRKKPRTPPVTLAAARENDLAFDWENYTPPVAHRLGVQEVEASIETLRNYIDWTPFFMTWSLAGKYPRILEDEVVGEEAKRLFKDANDMLDKLSAEKLLNPRGVVGLFPANRVGDDVEIYRDETRTHVLTVSRHLRQQTEKVGFANYCLSDFVAPKTSGKADYIGAFAVTGGLEEDTLADAFEAQHDDYNKIMVKALSDRLAEAFAEYLHERVRKVYWGYAPNENLSNEELIRENYQGIRPAPGYPACPEHTEKGTIWELLDVETHTGMKLTESFAMWPGASVSGWYFSHPDSKYYAVAQIQRDQVEDYALRKGMSVTEVERWLAPNLGYDAD

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
KU505137
EMBL· GenBank· DDBJ
AMK07455.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

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