ID A0A3Q0R006_AMPCI Unreviewed; 1213 AA.
AC A0A3Q0R006;
DT 10-APR-2019, integrated into UniProtKB/TrEMBL.
DT 10-APR-2019, sequence version 1.
DT 27-MAR-2024, entry version 25.
DE RecName: Full=Methionine synthase {ECO:0000256|ARBA:ARBA00012032, ECO:0000256|PIRNR:PIRNR000381};
DE EC=2.1.1.13 {ECO:0000256|ARBA:ARBA00012032, ECO:0000256|PIRNR:PIRNR000381};
DE AltName: Full=5-methyltetrahydrofolate--homocysteine methyltransferase {ECO:0000256|PIRNR:PIRNR000381};
OS Amphilophus citrinellus (Midas cichlid) (Cichlasoma citrinellum).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Actinopterygii; Neopterygii; Teleostei; Neoteleostei; Acanthomorphata;
OC Ovalentaria; Cichlomorphae; Cichliformes; Cichlidae; New World cichlids;
OC Cichlasomatinae; Heroini; Amphilophus.
OX NCBI_TaxID=61819 {ECO:0000313|Ensembl:ENSACIP00000003211.1, ECO:0000313|Proteomes:UP000261340};
RN [1] {ECO:0000313|Ensembl:ENSACIP00000003211.1}
RP IDENTIFICATION.
RG Ensembl;
RL Submitted (SEP-2023) to UniProtKB.
CC -!- FUNCTION: Catalyzes the transfer of a methyl group from
CC methylcob(III)alamin (MeCbl) to homocysteine, yielding enzyme-bound
CC cob(I)alamin and methionine in the cytosol. MeCbl is an active form of
CC cobalamin (vitamin B12) used as a cofactor for methionine biosynthesis.
CC Cob(I)alamin form is regenerated to MeCbl by a transfer of a methyl
CC group from 5-methyltetrahydrofolate. The processing of cobalamin in the
CC cytosol occurs in a multiprotein complex composed of at least MMACHC,
CC MMADHC, MTRR (methionine synthase reductase) and MTR which may
CC contribute to shuttle safely and efficiently cobalamin towards MTR in
CC order to produce methionine. {ECO:0000256|PIRNR:PIRNR000381}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(6S)-5-methyl-5,6,7,8-tetrahydrofolate + L-homocysteine =
CC (6S)-5,6,7,8-tetrahydrofolate + L-methionine; Xref=Rhea:RHEA:11172,
CC ChEBI:CHEBI:18608, ChEBI:CHEBI:57453, ChEBI:CHEBI:57844,
CC ChEBI:CHEBI:58199; EC=2.1.1.13;
CC Evidence={ECO:0000256|PIRNR:PIRNR000381};
CC -!- COFACTOR:
CC Name=Zn(2+); Xref=ChEBI:CHEBI:29105;
CC Evidence={ECO:0000256|ARBA:ARBA00001947,
CC ECO:0000256|PIRNR:PIRNR000381, ECO:0000256|PROSITE-ProRule:PRU00333};
CC -!- COFACTOR:
CC Name=methylcob(III)alamin; Xref=ChEBI:CHEBI:28115;
CC Evidence={ECO:0000256|ARBA:ARBA00001956,
CC ECO:0000256|PIRNR:PIRNR000381, ECO:0000256|PIRSR:PIRSR000381-1};
CC -!- PATHWAY: Amino-acid biosynthesis; L-methionine biosynthesis via de novo
CC pathway; L-methionine from L-homocysteine (MetH route): step 1/1.
CC {ECO:0000256|ARBA:ARBA00005178, ECO:0000256|PIRNR:PIRNR000381}.
CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000256|PIRNR:PIRNR000381}.
CC -!- DOMAIN: Modular enzyme with four functionally distinct domains. The
CC isolated Hcy-binding domain catalyzes methyl transfer from free
CC methylcobalamin to homocysteine. The Hcy-binding domain in association
CC with the pterin-binding domain catalyzes the methylation of
CC cob(I)alamin by methyltetrahydrofolate and the methylation of
CC homocysteine. The B12-binding domain binds the cofactor. The AdoMet
CC activation domain binds S-adenosyl-L-methionine. Under aerobic
CC conditions cob(I)alamin can be converted to inactive cob(II)alamin.
CC Reductive methylation by S-adenosyl-L-methionine and flavodoxin
CC regenerates methylcobalamin. {ECO:0000256|PIRNR:PIRNR000381}.
CC -!- SIMILARITY: Belongs to the vitamin-B12 dependent methionine synthase
CC family. {ECO:0000256|ARBA:ARBA00010398}.
CC ---------------------------------------------------------------------------
CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC ---------------------------------------------------------------------------
DR STRING; 61819.ENSACIP00000003211; -.
DR Ensembl; ENSACIT00000003321.1; ENSACIP00000003211.1; ENSACIG00000002494.1.
DR GeneTree; ENSGT00420000029824; -.
DR OMA; ADCIAMS; -.
DR UniPathway; UPA00051; UER00081.
DR Proteomes; UP000261340; Unplaced.
DR GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR GO; GO:0031419; F:cobalamin binding; IEA:UniProtKB-UniRule.
DR GO; GO:0008705; F:methionine synthase activity; IEA:UniProtKB-UniRule.
DR GO; GO:0008270; F:zinc ion binding; IEA:UniProtKB-UniRule.
DR GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR GO; GO:0042558; P:pteridine-containing compound metabolic process; IEA:InterPro.
DR CDD; cd02069; methionine_synthase_B12_BD; 1.
DR CDD; cd00740; MeTr; 1.
DR Gene3D; 3.40.50.280; Cobalamin-binding domain; 1.
DR Gene3D; 1.10.288.10; Cobalamin-dependent Methionine Synthase, domain 2; 1.
DR Gene3D; 3.20.20.20; Dihydropteroate synthase-like; 1.
DR Gene3D; 3.20.20.330; Homocysteine-binding-like domain; 1.
DR Gene3D; 1.10.1240.10; Methionine synthase domain; 1.
DR Gene3D; 3.10.196.10; Vitamin B12-dependent methionine synthase, activation domain; 1.
DR InterPro; IPR003759; Cbl-bd_cap.
DR InterPro; IPR006158; Cobalamin-bd.
DR InterPro; IPR036724; Cobalamin-bd_sf.
DR InterPro; IPR011005; Dihydropteroate_synth-like_sf.
DR InterPro; IPR003726; HCY_dom.
DR InterPro; IPR036589; HCY_dom_sf.
DR InterPro; IPR033706; Met_synthase_B12-bd.
DR InterPro; IPR011822; MetH.
DR InterPro; IPR036594; Meth_synthase_dom.
DR InterPro; IPR000489; Pterin-binding_dom.
DR InterPro; IPR004223; VitB12-dep_Met_synth_activ_dom.
DR InterPro; IPR037010; VitB12-dep_Met_synth_activ_sf.
DR NCBIfam; TIGR02082; metH; 1.
DR PANTHER; PTHR45833; METHIONINE SYNTHASE; 1.
DR PANTHER; PTHR45833:SF1; METHIONINE SYNTHASE; 1.
DR Pfam; PF02310; B12-binding; 1.
DR Pfam; PF02607; B12-binding_2; 1.
DR Pfam; PF02965; Met_synt_B12; 1.
DR Pfam; PF00809; Pterin_bind; 1.
DR Pfam; PF02574; S-methyl_trans; 1.
DR PIRSF; PIRSF000381; MetH; 1.
DR SMART; SM01018; B12-binding_2; 1.
DR SUPFAM; SSF52242; Cobalamin (vitamin B12)-binding domain; 1.
DR SUPFAM; SSF51717; Dihydropteroate synthetase-like; 1.
DR SUPFAM; SSF82282; Homocysteine S-methyltransferase; 1.
DR SUPFAM; SSF56507; Methionine synthase activation domain-like; 1.
DR SUPFAM; SSF47644; Methionine synthase domain; 1.
DR PROSITE; PS50974; ADOMET_ACTIVATION; 1.
DR PROSITE; PS51332; B12_BINDING; 1.
DR PROSITE; PS51337; B12_BINDING_NTER; 1.
DR PROSITE; PS50970; HCY; 1.
DR PROSITE; PS50972; PTERIN_BINDING; 1.
PE 3: Inferred from homology;
KW Amino-acid biosynthesis {ECO:0000256|ARBA:ARBA00022605,
KW ECO:0000256|PIRNR:PIRNR000381};
KW Cobalamin {ECO:0000256|ARBA:ARBA00022628, ECO:0000256|PIRNR:PIRNR000381};
KW Cobalt {ECO:0000256|ARBA:ARBA00023285, ECO:0000256|PIRNR:PIRNR000381};
KW Cytoplasm {ECO:0000256|PIRNR:PIRNR000381};
KW Metal-binding {ECO:0000256|ARBA:ARBA00022723,
KW ECO:0000256|PIRNR:PIRNR000381};
KW Methionine biosynthesis {ECO:0000256|ARBA:ARBA00023167,
KW ECO:0000256|PIRNR:PIRNR000381};
KW Methyltransferase {ECO:0000256|ARBA:ARBA00022603,
KW ECO:0000256|PIRNR:PIRNR000381}; Repeat {ECO:0000256|ARBA:ARBA00022737};
KW S-adenosyl-L-methionine {ECO:0000256|ARBA:ARBA00022691,
KW ECO:0000256|PIRNR:PIRNR000381};
KW Transferase {ECO:0000256|ARBA:ARBA00022679, ECO:0000256|PIRNR:PIRNR000381};
KW Zinc {ECO:0000256|ARBA:ARBA00022833, ECO:0000256|PIRNR:PIRNR000381}.
FT DOMAIN 1..300
FT /note="Hcy-binding"
FT /evidence="ECO:0000259|PROSITE:PS50970"
FT DOMAIN 333..592
FT /note="Pterin-binding"
FT /evidence="ECO:0000259|PROSITE:PS50972"
FT DOMAIN 624..721
FT /note="B12-binding N-terminal"
FT /evidence="ECO:0000259|PROSITE:PS51337"
FT DOMAIN 734..869
FT /note="B12-binding"
FT /evidence="ECO:0000259|PROSITE:PS51332"
FT DOMAIN 870..1212
FT /note="AdoMet activation"
FT /evidence="ECO:0000259|PROSITE:PS50974"
FT BINDING 232
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-1,
FT ECO:0000256|PROSITE-ProRule:PRU00333"
FT BINDING 285
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-1,
FT ECO:0000256|PROSITE-ProRule:PRU00333"
FT BINDING 286
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-1,
FT ECO:0000256|PROSITE-ProRule:PRU00333"
FT BINDING 671
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 744..748
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 747
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /ligand_part="Co"
FT /ligand_part_id="ChEBI:CHEBI:27638"
FT /note="axial binding residue"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-1"
FT BINDING 792
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 796
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 848
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 920
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 1119
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 1174..1175
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
SQ SEQUENCE 1213 AA; 134357 MW; 80B2640190AB9FEE CRC64;
RIMVLDGGMG TMIQQHKLGE EDFRGDEFKT HALPLKGNND ILSITQPDII YKIHKEYLLA
GADIIETNTF SSTSIAQADY GLEHMTYRLN KASALLARRA ADDITKQSGY KRYVAGAVGP
TNKTLSVSPC VERPDFRNIT FDELVEAYSE QVRGLLDGGV DILLVETIFD TANAKAALFA
IDLLFEKSHE RKPIFISGTI VDRSGRTLSG QTGEAFVVSV SHANPLCIGL NCALGATEMR
PFIEAIGKST TAFIICYPNA DRCSVLQSHN DFFAMDGLVN IVGGCCGTTP SHIRAISEAV
KHCQPRAPVA DIYQDYLLLS GLEPFTIGPH TNFVNIGERC NVAGSRKFAK LIMAGNYEEA
LSIAKAQVEM GAQVLDINMD EGMLDGPTAM ARFCNFIASE PDIARVPLCI DSSNFSVIEA
GLKCCQGKCI VNSISLKEGE QEFLLRAATV KRYGAAVVVM AFDEEGQATD TERKVEICTR
AYKLLISKVG FNPNNIIFDP NILTIGTGMD EHNEYGISFI RATKLIKEXL PRARVSGGLS
NLSFSFRGME AIREAMHGVF LYHAIKDGMD MGIVNAGNLP VYDNIDKELL LLCENLIWNR
DADATEKLLA YAQNNAKGGK KAVQTDEWRE QCVEERLEYA LIKGIEKYVV EDVEECRIQV
HRYTRPLRII EGPLMNGMKV VGDLFGAGKM FLPQVIKSAR VMKKAVSYLI PFMEKERQEM
MAASGSSDET NPYQGTVVLA TVKGDVHDIG KNIVGVVLGC NNFRVIDLGV MVPCDKILRA
AITQKADVIG LSGLITPSLD EMIYVAKEME RLGMTTPLLI GGATTSKIHT AVKIAPRYSF
PVIHVLDASR SVVVCSQLLD ETSKEEYFEE LKEEYEAIRQ EHYESLKVRS AILCVSVCPQ
FLGTRVFELY NLNSLVDFID WKPFFDVWQL RGKYPNRGYP KIFNDKTVGS EARRVFDDAQ
QLLNQIFDNS SLKGRGLVGF WRAQSSGDDI RVYKDDVTVH RDTKPITTFH GLRQQVEKDS
SSSEPYLCVS DFVAPVDSGV ADYIGLFAVG VFGAEELSQQ FQAQGDDYSS IMVKALADRL
AEAFAEELHV RVRKELWGYS ADEALHTSDL HRIRYQGIRP AAGYPSQPDH TEKITMWNLA
NIQEKTGIGL TESLAMTPAA SVSGLYFSNP QASYFAVGKI TKEQVGDYAR RKEMNVDEVE
RWLAPILGYD NEV
//
