Q55786 · METH_SYNY3
- ProteinMethionine synthase
- GenemetH
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids1195 (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 (By similarity).
Miscellaneous
L-homocysteine is bound via the zinc atom.
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:
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.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 228 | Zn2+ (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 294 | Zn2+ (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 295 | Zn2+ (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 734-738 | methylcob(III)alamin (UniProtKB | ChEBI) | ||||
Sequence: GDVHD | ||||||
Binding site | 737 | Co (UniProtKB | ChEBI) of methylcob(III)alamin (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 782 | methylcob(III)alamin (UniProtKB | ChEBI) | ||||
Sequence: S | ||||||
Binding site | 838 | methylcob(III)alamin (UniProtKB | ChEBI) | ||||
Sequence: A | ||||||
Binding site | 945 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 1138 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: R | ||||||
Binding site | 1192-1193 | S-adenosyl-L-methionine (UniProtKB | ChEBI) | ||||
Sequence: YF |
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 | methionine biosynthetic 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
- Strains
- Taxonomic lineageBacteria > Cyanobacteriota > Cyanophyceae > Synechococcales > Merismopediaceae > Synechocystis
Accessions
- Primary accessionQ55786
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000204537 | 1-1195 | Methionine synthase | |||
Sequence: MKSAFLDRIHSPDRPVLVFDGAMGTNLQVQNLTAADFGGAEYEGCNEYLVHTKPEAVATVHRAFYEAGADVVETDTFGGTPLVLAEYDLADQSYYLNKAAAELAKAVAAEFSTPEKPRFVAGSMGPGTKLPTLGHVDYDSLKDAYVVQVRGLYDGGVDLLLVETCQDVLQIKAALNAIEQVFAEKGDRLPLMVSVTMETMGTMLVGTEMAAALAILEPYPIDILGLNCATGPDLMKEHVKYLSEHSPFVVSCIPNAGLPENVGGQAFYRLTPMELQMSLMHFIEDLGVQVIGGCCGTRPDHIKALADIAKDLQPKQRQPHYEPSAASIYSTQTYAQENSFLIIGERLNASGSKKCRDLLNAEDWDSLVSLAKSQVKEGAQILDVNVDYVGRDGVRDMKELASRLVNNVTLPLMLDSTEWQKMEAGLKVAGGKCILNSTNYEDGEERFYKVLEIAKEYGAGIVIGTIDEDGMGRTADKKFEIAKRAYEAAIAFGIPATEIFFDPLALPISTGIEEDRENGKATVDAIRRIRQELPDCHILLGVSNVSFGLNPAARQVLNSIFLHECMQVGMDAAIVSANKILPLAKIDPEQQQVCLDLIYDRREFEGERCTYDPLTKLTTLFEGKTTKRDKSGDANLPVEERLKRHIIDGERLGLEEALNEALKLYAPLDIINIYLLDGMKVVGELFGSGQMQLPFVLQSAQTMKAAVAFLEPHMDKDDSADNAKGTFLIATVKGDVHDIGKNLVDIILSNNGYRVVNLGIKQPVENIIEAYKKHRPDCIAMSGLLVKSTAFMKENLEVFNQEGITVPVILGGAALTPKFVHQDCQNTYKGQVIYGKDAFADLHFMDKLMPAKNSHNWDDFQGFLGEYATENGHNVTTDDGAKTNFGIEEEKLIDASEQSREPEVIDTVRSEAVDPDLERPVPPFWGTKILQSSDISLDEVFPLLDLQALFVGQWQFRKPREQSREEYEQFLAEKVHPILAEWKGKVMAENLLHPTVVYGYFPCQSQGNTLLIYDPELVSQNNGQIPPDATAIAKFEFPRQKSGRRLCIADFFASKESGITDVFPLQAVTVGEIATEYARKLFAGDNYTDYLYFHGMAVQMAEALAEWTHQRIRQELGFGHLDPDNIRDLLQQRYQGSRYSFGYPACPNMQDQYTQLELLQTERIGLYMDESEQVYPEQSTTAIISYHPAAKYFSA |
Proteomic databases
Interaction
Protein-protein interaction databases
Structure
Family & Domains
Features
Showing features for domain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Domain | 1-309 | Hcy-binding | ||||
Sequence: MKSAFLDRIHSPDRPVLVFDGAMGTNLQVQNLTAADFGGAEYEGCNEYLVHTKPEAVATVHRAFYEAGADVVETDTFGGTPLVLAEYDLADQSYYLNKAAAELAKAVAAEFSTPEKPRFVAGSMGPGTKLPTLGHVDYDSLKDAYVVQVRGLYDGGVDLLLVETCQDVLQIKAALNAIEQVFAEKGDRLPLMVSVTMETMGTMLVGTEMAAALAILEPYPIDILGLNCATGPDLMKEHVKYLSEHSPFVVSCIPNAGLPENVGGQAFYRLTPMELQMSLMHFIEDLGVQVIGGCCGTRPDHIKALADIA | ||||||
Domain | 340-599 | Pterin-binding | ||||
Sequence: FLIIGERLNASGSKKCRDLLNAEDWDSLVSLAKSQVKEGAQILDVNVDYVGRDGVRDMKELASRLVNNVTLPLMLDSTEWQKMEAGLKVAGGKCILNSTNYEDGEERFYKVLEIAKEYGAGIVIGTIDEDGMGRTADKKFEIAKRAYEAAIAFGIPATEIFFDPLALPISTGIEEDRENGKATVDAIRRIRQELPDCHILLGVSNVSFGLNPAARQVLNSIFLHECMQVGMDAAIVSANKILPLAKIDPEQQQVCLDLIY | ||||||
Domain | 629-722 | B12-binding N-terminal | ||||
Sequence: DKSGDANLPVEERLKRHIIDGERLGLEEALNEALKLYAPLDIINIYLLDGMKVVGELFGSGQMQLPFVLQSAQTMKAAVAFLEPHMDKDDSADN | ||||||
Domain | 724-859 | B12-binding | ||||
Sequence: KGTFLIATVKGDVHDIGKNLVDIILSNNGYRVVNLGIKQPVENIIEAYKKHRPDCIAMSGLLVKSTAFMKENLEVFNQEGITVPVILGGAALTPKFVHQDCQNTYKGQVIYGKDAFADLHFMDKLMPAKNSHNWDD | ||||||
Domain | 896-1195 | AdoMet activation | ||||
Sequence: SEQSREPEVIDTVRSEAVDPDLERPVPPFWGTKILQSSDISLDEVFPLLDLQALFVGQWQFRKPREQSREEYEQFLAEKVHPILAEWKGKVMAENLLHPTVVYGYFPCQSQGNTLLIYDPELVSQNNGQIPPDATAIAKFEFPRQKSGRRLCIADFFASKESGITDVFPLQAVTVGEIATEYARKLFAGDNYTDYLYFHGMAVQMAEALAEWTHQRIRQELGFGHLDPDNIRDLLQQRYQGSRYSFGYPACPNMQDQYTQLELLQTERIGLYMDESEQVYPEQSTTAIISYHPAAKYFSA |
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
Belongs to the vitamin-B12 dependent methionine synthase family.
Keywords
- Domain
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length1,195
- Mass (Da)132,540
- Last updated1996-11-01 v1
- Checksum1D9635B1B1DDB583
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
BA000022 EMBL· GenBank· DDBJ | BAA10438.1 EMBL· GenBank· DDBJ | Genomic DNA |