G3V8A4 · G3V8A4_RAT

Function

function

Catalyzes the transfer of a methyl group from methylcob(III)alamin (MeCbl) to homocysteine, yielding enzyme-bound cob(I)alamin and methionine in the cytosol. MeCbl is an active form of cobalamin (vitamin B12) used as a cofactor for methionine biosynthesis. Cob(I)alamin form is regenerated to MeCbl by a transfer of a methyl group from 5-methyltetrahydrofolate. The processing of cobalamin in the cytosol occurs in a multiprotein complex composed of at least MMACHC, MMADHC, MTRR (methionine synthase reductase) and MTR which may contribute to shuttle safely and efficiently cobalamin towards MTR in order to produce methionine.

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 site248Zn2+ (UniProtKB | ChEBI)
Binding site311Zn2+ (UniProtKB | ChEBI)
Binding site312Zn2+ (UniProtKB | ChEBI)
Binding site697methylcob(III)alamin (UniProtKB | ChEBI)
Binding site770-774methylcob(III)alamin (UniProtKB | ChEBI)
Binding site773Co (UniProtKB | ChEBI) of methylcob(III)alamin (UniProtKB | ChEBI); axial binding residue
Binding site818methylcob(III)alamin (UniProtKB | ChEBI)
Binding site822methylcob(III)alamin (UniProtKB | ChEBI)
Binding site874methylcob(III)alamin (UniProtKB | ChEBI)
Binding site962S-adenosyl-L-methionine (UniProtKB | ChEBI)
Binding site1160S-adenosyl-L-methionine (UniProtKB | ChEBI)
Binding site1215-1216S-adenosyl-L-methionine (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentcytosol
Molecular Functioncobalamin binding
Molecular Functionmethionine synthase activity
Molecular Functionzinc ion binding
Biological Processaxon regeneration
Biological Processcellular response to nitric oxide
Biological Processcobalamin metabolic process
Biological Processmethionine biosynthetic process
Biological Processmethylation
Biological Processpteridine-containing compound metabolic process
Biological Processresponse to axon injury

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

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

Gene names

    • Name
      Mtr

Organism names

  • Taxonomic identifier
  • Organism
  • Strain
    • Brown Norway
  • Taxonomic lineage
    Eukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Euarchontoglires > Glires > Rodentia > Myomorpha > Muroidea > Muridae > Murinae > Rattus

Accessions

  • Primary accession
    G3V8A4

Proteomes

Organism-specific databases

Subcellular Location

Keywords

Expression

Gene expression databases

Structure

Family & Domains

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

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    1,253
  • Mass (Da)
    139,191
  • Last updated
    2011-11-16 v1
  • Checksum
    CFBD40BB66EBD75E
MKKTLQDEIEAILRKRIMVLDGGMGTMIQRYKLSEENFQGQEFKDHSRPLKGNNDILSITQPDVIYQIHKEYLLAGADIIETNTFSSTSIAQADYGLEHLAYRMNKCSADVARKAAEEITLQTGVKRFVAGSLGPTNKTLSVSPSVERPDYRNITFDELVEAYQEQAKGLLDGGVDILLIETIFDTANAKAALFALQKLFEENYASPRPIFISGTIVDKSGRTLSGQTGEAFVTSVSHSDPLCIGLNCALGAAEMRPFIETIGKCTTAYVLCYPNAGLPNTFGDYDETPAMMAMHLKDFAVDGLVNVVGGCCGSTPDHIREIAEAVKNCKPRVPPDSVFEGHMLLSGLEPFRIGPYTNFVNIGERCNVAGSKKFAKLIMAGNYEEALSVAKVQVEMGAQVLDINMDDGMLDGPSAMTKFCNFIASEPDIAKVPLCIDSSNFAVIEAGLKCCQGKCIVNSISLKEGEEDFLEKARKIKKFGAAVVVMAFDEEGQATETDVKVSVCTRAYHLLVEKVGFNPNDIIFDPNILTIGTGMEEHNLYAINFIHATRVIKETLPGVRISGGLSNLSFAFRGMDAIREAMHGVFLYHAIKFGMDMGIVNAGSLPVYDDIHKDLLQLCEDLIWNRDAEATEKLLRYAQTHGKGGKKVIQTDEWRNGSIEERLEYALVKGIEKHIVEDTEEARLNREKYPRPLNIIEGPLMNGMKVVGDLFGAGKMFLPQVIKSARVMKKAVGHLIPFMEKEREEARVLNGSVEEEDPYQGTIVLATVKGDVHDIGKNIVGVVLGCNNFRVIDLGVMTPCDKILQAALDHKADIIGLSGLITPSLDEMIFVAKEMERLAIKIPLLIGGATTSRTHTAVKIAPRYSAPVIHVLDASKSVVVCSQLLDENLKDDYFEEILEEYEDIRQDHYESLKERKYLPLSQARKHSFHIDWLSEPHPVKPTFIGTQVFEDYNLQKLVDYIDWKPFFDVWQLRGKYPNRGFPKIFNDKAVGEEARKVYEDAQNMLNILISRKKLRARGVVGFWPAQSVQDDIHLYAEGAVPQAAEPIATFYGLRQQAEKDSSSTDPYHCLSDFVAPLHSGVRDYLGLFAVACFGVEELSKAYEDDGDDYSSIMVKALGDRLAEAFAEELHERVRRELWAYCGSEQLGVTDLRKLRYEGIRPAPGYPSQPDHTEKLTMWRLANIEQATGIRLTESLAMAPASAVSGLYFSNVKSKYFAVGKISKDQIEDYALRKNMSVAEVEKWLGPILGYDTD

Computationally mapped potential isoform sequences

There is 1 potential isoform mapped to this entry

View all
EntryEntry nameGene nameLength
Q9Z2Q4METH_RATMtr1253

Keywords

Genome annotation databases

Similar Proteins

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