Q55786 · METH_SYNY3

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 site228Zn2+ (UniProtKB | ChEBI)
Binding site294Zn2+ (UniProtKB | ChEBI)
Binding site295Zn2+ (UniProtKB | ChEBI)
Binding site734-738methylcob(III)alamin (UniProtKB | ChEBI)
Binding site737Co (UniProtKB | ChEBI) of methylcob(III)alamin (UniProtKB | ChEBI); axial binding residue
Binding site782methylcob(III)alamin (UniProtKB | ChEBI)
Binding site838methylcob(III)alamin (UniProtKB | ChEBI)
Binding site945S-adenosyl-L-methionine (UniProtKB | ChEBI)
Binding site1138S-adenosyl-L-methionine (UniProtKB | ChEBI)
Binding site1192-1193S-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 Processmethionine biosynthetic 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
    • Methionine synthase, vitamin-B12 dependent (MS)

Gene names

    • Name
      metH
    • Ordered locus names
      slr0212

Organism names

Accessions

  • Primary accession
    Q55786

Proteomes

Subcellular Location

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00002045371-1195Methionine synthase

Proteomic databases

Interaction

Protein-protein interaction databases

Structure

Family & Domains

Features

Showing features for domain.

TypeIDPosition(s)Description
Domain1-309Hcy-binding
Domain340-599Pterin-binding
Domain629-722B12-binding N-terminal
Domain724-859B12-binding
Domain896-1195AdoMet 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
    1,195
  • Mass (Da)
    132,540
  • Last updated
    1996-11-01 v1
  • Checksum
    1D9635B1B1DDB583
MKSAFLDRIHSPDRPVLVFDGAMGTNLQVQNLTAADFGGAEYEGCNEYLVHTKPEAVATVHRAFYEAGADVVETDTFGGTPLVLAEYDLADQSYYLNKAAAELAKAVAAEFSTPEKPRFVAGSMGPGTKLPTLGHVDYDSLKDAYVVQVRGLYDGGVDLLLVETCQDVLQIKAALNAIEQVFAEKGDRLPLMVSVTMETMGTMLVGTEMAAALAILEPYPIDILGLNCATGPDLMKEHVKYLSEHSPFVVSCIPNAGLPENVGGQAFYRLTPMELQMSLMHFIEDLGVQVIGGCCGTRPDHIKALADIAKDLQPKQRQPHYEPSAASIYSTQTYAQENSFLIIGERLNASGSKKCRDLLNAEDWDSLVSLAKSQVKEGAQILDVNVDYVGRDGVRDMKELASRLVNNVTLPLMLDSTEWQKMEAGLKVAGGKCILNSTNYEDGEERFYKVLEIAKEYGAGIVIGTIDEDGMGRTADKKFEIAKRAYEAAIAFGIPATEIFFDPLALPISTGIEEDRENGKATVDAIRRIRQELPDCHILLGVSNVSFGLNPAARQVLNSIFLHECMQVGMDAAIVSANKILPLAKIDPEQQQVCLDLIYDRREFEGERCTYDPLTKLTTLFEGKTTKRDKSGDANLPVEERLKRHIIDGERLGLEEALNEALKLYAPLDIINIYLLDGMKVVGELFGSGQMQLPFVLQSAQTMKAAVAFLEPHMDKDDSADNAKGTFLIATVKGDVHDIGKNLVDIILSNNGYRVVNLGIKQPVENIIEAYKKHRPDCIAMSGLLVKSTAFMKENLEVFNQEGITVPVILGGAALTPKFVHQDCQNTYKGQVIYGKDAFADLHFMDKLMPAKNSHNWDDFQGFLGEYATENGHNVTTDDGAKTNFGIEEEKLIDASEQSREPEVIDTVRSEAVDPDLERPVPPFWGTKILQSSDISLDEVFPLLDLQALFVGQWQFRKPREQSREEYEQFLAEKVHPILAEWKGKVMAENLLHPTVVYGYFPCQSQGNTLLIYDPELVSQNNGQIPPDATAIAKFEFPRQKSGRRLCIADFFASKESGITDVFPLQAVTVGEIATEYARKLFAGDNYTDYLYFHGMAVQMAEALAEWTHQRIRQELGFGHLDPDNIRDLLQQRYQGSRYSFGYPACPNMQDQYTQLELLQTERIGLYMDESEQVYPEQSTTAIISYHPAAKYFSA

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
BA000022
EMBL· GenBank· DDBJ
BAA10438.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

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