A0A126QFW5 · A0A126QFW5_9ENTR
- ProteinMethionine synthase
- GenemthM
- StatusUniProtKB unreviewed (TrEMBL)
- Organism
- Amino acids970 (go to sequence)
- Protein existenceInferred from homology
- Annotation score3/5
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.
Catalytic activity
- (6S)-5-methyl-5,6,7,8-tetrahydrofolate + L-homocysteine = (6S)-5,6,7,8-tetrahydrofolate + L-methionine
Cofactor
Protein has several cofactor binding sites:
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.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 53 | Zn2+ (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 54 | Zn2+ (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 437 | methylcob(III)alamin (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Binding site | 499-503 | methylcob(III)alamin (UniProtKB | ChEBI) | ||||
Sequence: GDVHD | ||||||
Binding site | 502 | Co (UniProtKB | ChEBI) of methylcob(III)alamin (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 547 | methylcob(III)alamin (UniProtKB | ChEBI) | ||||
Sequence: S | ||||||
Binding site | 551 | methylcob(III)alamin (UniProtKB | ChEBI) | ||||
Sequence: T | ||||||
Binding site | 603 | methylcob(III)alamin (UniProtKB | ChEBI) | ||||
Sequence: A | ||||||
Binding site | 689 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 877 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: R | ||||||
Binding site | 932-933 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: YY |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytosol | |
Molecular Function | cobalamin binding | |
Molecular Function | methionine synthase activity | |
Molecular Function | zinc ion binding | |
Biological Process | homocysteine metabolic process | |
Biological Process | methylation | |
Biological Process | tetrahydrofolate metabolic process |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameMethionine synthase
- EC number
- Alternative names
Gene names
Organism names
- Organism
- Strain
- Taxonomic lineageBacteria > Pseudomonadota > Gammaproteobacteria > Enterobacterales > Enterobacteriaceae > Klebsiella/Raoultella group > Klebsiella
Accessions
- Primary accessionA0A126QFW5
Subcellular Location
UniProt Annotation
GO Annotation
Structure
Family & Domains
Features
Showing features for domain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Domain | 1-68 | Hcy-binding | ||||
Sequence: MQELSRIAECYVTAHPNAGLPNAFGEYDLDADTMATQIREWAEAGFLNVVGGCCGTTPEHIAAMSRAV | ||||||
Domain | 99-360 | Pterin-binding | ||||
Sequence: FVNVGERTNVTGSAKFKRLIKEEKYNEALAVARQQVESGAQIIDINMDEGMLDAEAAMVRFLNLIAGEPDIARVPIMIDSSKWDVIEKGLKCIQGKGIVNSISMKEGIEPFIQHAKKVRRYGAAVVVMAFDEVGQADTRERKIEICRRAYNILTKEVGFPPEDIIFDPNIFAVATGIEEHNNYAQDFIGACEDIKRELPHALISGGVSNVSFSFRGNDPVREAIHAVFLYYAIRNGMDMGIVNAGQLAIYDDLPAELRDAVE | ||||||
Domain | 393-487 | B12-binding N-terminal | ||||
Sequence: QQAEWRSWDVKKRLEYSLVKGITEFIEQDTEEARQQAERPIQVIEGPLMDGMNVVGDLFGEGKMFLPQVVKSARVMKQAVAYLEPYIEASKEKGS | ||||||
Domain | 489-624 | B12-binding | ||||
Sequence: NGKMVIATVKGDVHDIGKNIVGVVLQCNNYEIIDLGVMVPADKILKTAREVNADLIGLSGLITPSLDEMVNVAKEMERQGFSIPLLIGGATTSKAHTAVKIEQNYSGPTVYVQNASRTVGVVAALLSDTQHDDFVA | ||||||
Domain | 640-970 | AdoMet activation | ||||
Sequence: KKPRTPPVTLAAARENDLAFDWENYTPPVAHRLGVQEVEASIETLRNYIDWTPFFMTWSLAGKYPRILEDEVVGEEAKRLFKDANDMLDKLSAEKLLNPRGVVGLFPANRVGDDVEIYRDETRTHVLTVSRHLRQQTEKVGFANYCLSDFVAPKTSGKADYIGAFAVTGGLEEDTLADAFEAQHDDYNKIMVKALSDRLAEAFAEYLHERVRKVYWGYAPNENLSNEELIRENYQGIRPAPGYPACPEHTEKGTIWELLDVETHTGMKLTESFAMWPGASVSGWYFSHPDSKYYAVAQIQRDQVEDYALRKGMSVTEVERWLAPNLGYDAD |
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
- Domain
Family and domain databases
Sequence
- Sequence statusComplete
- Length970
- Mass (Da)107,968
- Last updated2016-05-11 v1
- ChecksumF09925263F7CB705