ID   A0A1J4NLC1_9GAMM        Unreviewed;      1228 AA.
AC   A0A1J4NLC1;
DT   15-FEB-2017, integrated into UniProtKB/TrEMBL.
DT   15-FEB-2017, sequence version 1.
DT   27-NOV-2024, entry version 44.
DE   RecName: Full=Methionine synthase {ECO:0000256|ARBA:ARBA00013998, ECO:0000256|NCBIfam:TIGR02082};
DE            EC=2.1.1.13 {ECO:0000256|ARBA:ARBA00012032, ECO:0000256|NCBIfam:TIGR02082};
DE   AltName: Full=5-methyltetrahydrofolate--homocysteine methyltransferase {ECO:0000256|PIRNR:PIRNR000381};
GN   ORFNames=BK820_02005 {ECO:0000313|EMBL:OIJ39084.1};
OS   Acinetobacter sp. LCT-H3.
OC   Bacteria; Pseudomonadota; Gammaproteobacteria; Moraxellales; Moraxellaceae;
OC   Acinetobacter.
OX   NCBI_TaxID=1914307 {ECO:0000313|EMBL:OIJ39084.1, ECO:0000313|Proteomes:UP000186913};
RN   [1] {ECO:0000313|EMBL:OIJ39084.1, ECO:0000313|Proteomes:UP000186913}
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=LCT-H3 {ECO:0000313|EMBL:OIJ39084.1,
RC   ECO:0000313|Proteomes:UP000186913};
RA   Huang B.;
RT   "Draft genome sequence of strain LCT isolated from the Shenzhou X
RT   spacecraft of China.";
RL   Submitted (OCT-2016) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Catalyzes the transfer of a methyl group from methyl-
CC       cobalamin to homocysteine, yielding enzyme-bound cob(I)alamin and
CC       methionine. Subsequently, remethylates the cofactor using
CC       methyltetrahydrofolate. {ECO:0000256|ARBA:ARBA00025552,
CC       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|ARBA:ARBA00001700,
CC         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   -!- 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   -!- CAUTION: The sequence shown here is derived from an EMBL/GenBank/DDBJ
CC       whole genome shotgun (WGS) entry which is preliminary data.
CC       {ECO:0000313|EMBL:OIJ39084.1}.
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DR   EMBL; MODX01000002; OIJ39084.1; -; Genomic_DNA.
DR   RefSeq; WP_071319950.1; NZ_MODX01000002.1.
DR   AlphaFoldDB; A0A1J4NLC1; -.
DR   UniPathway; UPA00051; UER00081.
DR   Proteomes; UP000186913; Unassembled WGS sequence.
DR   GO; GO:0005829; C:cytosol; IEA:TreeGrafter.
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:0050667; P:homocysteine metabolic process; IEA:TreeGrafter.
DR   GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR   GO; GO:0046653; P:tetrahydrofolate metabolic process; IEA:TreeGrafter.
DR   CDD; cd02069; methionine_synthase_B12_BD; 1.
DR   CDD; cd00740; MeTr; 1.
DR   FunFam; 1.10.1240.10:FF:000001; Methionine synthase; 1.
DR   FunFam; 3.20.20.20:FF:000002; Methionine synthase; 1.
DR   FunFam; 3.20.20.330:FF:000001; Methionine synthase; 1.
DR   FunFam; 3.40.50.280:FF:000001; Methionine synthase; 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; IPR050554; Met_Synthase/Corrinoid.
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   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          4..322
FT                   /note="Hcy-binding"
FT                   /evidence="ECO:0000259|PROSITE:PS50970"
FT   DOMAIN          353..614
FT                   /note="Pterin-binding"
FT                   /evidence="ECO:0000259|PROSITE:PS50972"
FT   DOMAIN          651..745
FT                   /note="B12-binding N-terminal"
FT                   /evidence="ECO:0000259|PROSITE:PS51337"
FT   DOMAIN          747..883
FT                   /note="B12-binding"
FT                   /evidence="ECO:0000259|PROSITE:PS51332"
FT   DOMAIN          899..1228
FT                   /note="AdoMet activation"
FT                   /evidence="ECO:0000259|PROSITE:PS50974"
FT   BINDING         244
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         307
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         308
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         695
FT                   /ligand="methylcob(III)alamin"
FT                   /ligand_id="ChEBI:CHEBI:28115"
FT                   /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT   BINDING         757..761
FT                   /ligand="methylcob(III)alamin"
FT                   /ligand_id="ChEBI:CHEBI:28115"
FT                   /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT   BINDING         760
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         805
FT                   /ligand="methylcob(III)alamin"
FT                   /ligand_id="ChEBI:CHEBI:28115"
FT                   /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT   BINDING         809
FT                   /ligand="methylcob(III)alamin"
FT                   /ligand_id="ChEBI:CHEBI:28115"
FT                   /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT   BINDING         862
FT                   /ligand="methylcob(III)alamin"
FT                   /ligand_id="ChEBI:CHEBI:28115"
FT                   /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT   BINDING         949
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT   BINDING         1135
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT   BINDING         1190..1191
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
SQ   SEQUENCE   1228 AA;  135279 MW;  17BD4F3C873C5626 CRC64;
     MSTLATLKEL LAKRILIIDG AMGTMIQRHK LEEADYRGER FADWAYDLKG NNDLLVLTQP
     HIIQGIHEAY LEAGADIIET NTFNGTRVSM SDYHMEDLVP EINREAARLA KEACAKYSTP
     EKPRFVAGVI GPTSRTTSIS PNVNDPAFRN ITFDALKVDY IESTKALIEG GADIILIETV
     FDTLNAKAAI FAVKEVFKEI GYELPIMISG TITDASGRTL TGQTAEAFWN SMRHAEPISI
     GFNCALGADA MRPHVKTISD VADTFVSAHP NAGLPNAFGG YDETPEETAA FIKEFAESGL
     INITGGCCGT TPDHIRAIAQ AVEGIAPRQI PEIEPACRLS GLEPFNITKD SLFVNVGERT
     NVTGSKKFLR LIKEENFTEA LDVARQQVEA GAQIIDINMD EGMLDSQAAM VHFLNLIASE
     PDISRVPIML DSSKWEIIEA GLKCVQGKAV VNSISLKEGY DEFVERARLC RQYGAAVIVM
     AFDENGQADT AERKKEICKR SYDVLVNEVG FPSEDIIFDP NVFAVATGIE EHNNYGVDFI
     EATGWIKQNL PNAMISGGIS NVSFSFRGNE PVREAIHAVF LYHAIQKGLT MGIVNAGQLA
     IYDDIDAELK EAVEDVVLNR NQGESGQEAT EKLLTIAEKY RGQAGAQKAE ENLEWRNESV
     EKRLEYALVK GITTYIDQDT EEARLKSARP LDVIEGPLMA GMNVVGDLFG AGKMFLPQVV
     KSARVMKQAV AWLNPFIEAE KTQGEAKGKI LLATVKGDVH DIGKNIVGVV LGCNGYDIVD
     LGVMVPCEKI LQTAIDEKVD IIGLSGLITP SLDEMVFVAK EMQRKGFNIP LMIGGATTSK
     AHTAVKIAPQ YQNDGVFYTA DASRAVGVTT QLLSAEMKPQ LMADYAADYE KIRTRLANKQ
     PKAAKLSYKE SVENGFKIDF DKNAPVKPNF IGSQTFTNYP LETLVEYFDW TPFFISWSLA
     GKFPKILEDE VVGEAARDLY AQAQAMLKNI IDNKRFDARA TFSIYPANRT GSDTVAVTDE
     AGNVTHTFEH LRQQSDKVTG KANYSLADFI APKDVAQDYL GGFTVSIFGA EELSQEYKAK
     GDDYNAIMVQ ALGDRFAEAF AEHLHQRIRK EFWGYQPNES LDNEALIKEK YVGIRPAPGY
     PACPEHSEKA PLFDWLGTTE KMGTYLTSSF AMWPPSSVSG FYYANPETEY FNVGKISGDQ
     LEDYAKRKGW TLDEAKRWLA PNLDDSVV
//