ID Q3APY1_CHLCH Unreviewed; 1224 AA.
AC Q3APY1;
DT 22-NOV-2005, integrated into UniProtKB/TrEMBL.
DT 22-NOV-2005, sequence version 1.
DT 27-MAR-2024, entry version 127.
DE RecName: Full=Methionine synthase {ECO:0000256|ARBA:ARBA00013998, 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|ARBA:ARBA00031040, ECO:0000256|PIRNR:PIRNR000381};
GN OrderedLocusNames=Cag_1692 {ECO:0000313|EMBL:ABB28944.1};
OS Chlorobium chlorochromatii (strain CaD3).
OC Bacteria; Chlorobiota; Chlorobiia; Chlorobiales; Chlorobiaceae;
OC Chlorobium/Pelodictyon group; Chlorobium.
OX NCBI_TaxID=340177 {ECO:0000313|EMBL:ABB28944.1};
RN [1] {ECO:0000313|EMBL:ABB28944.1}
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=CaD3 {ECO:0000313|EMBL:ABB28944.1};
RG US DOE Joint Genome Institute;
RA Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C., Glavina T.,
RA Hammon N., Israni S., Pitluck S., Bryant D., Schmutz J., Larimer F.,
RA Land M., Kyrpides N., Ivanova N., Richardson P.;
RT "Complete sequence of Chlorobium chlorochromatii CaD3.";
RL Submitted (AUG-2005) 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}.
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DR EMBL; CP000108; ABB28944.1; -; Genomic_DNA.
DR AlphaFoldDB; Q3APY1; -.
DR STRING; 340177.Cag_1692; -.
DR KEGG; cch:Cag_1692; -.
DR eggNOG; COG0646; Bacteria.
DR eggNOG; COG1410; Bacteria.
DR HOGENOM; CLU_004914_2_0_10; -.
DR UniPathway; UPA00051; UER00081.
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 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..304
FT /note="Hcy-binding"
FT /evidence="ECO:0000259|PROSITE:PS50970"
FT DOMAIN 335..600
FT /note="Pterin-binding"
FT /evidence="ECO:0000259|PROSITE:PS50972"
FT DOMAIN 627..721
FT /note="B12-binding N-terminal"
FT /evidence="ECO:0000259|PROSITE:PS51337"
FT DOMAIN 726..861
FT /note="B12-binding"
FT /evidence="ECO:0000259|PROSITE:PS51332"
FT DOMAIN 877..1224
FT /note="AdoMet activation"
FT /evidence="ECO:0000259|PROSITE:PS50974"
FT BINDING 226
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 289
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 290
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 736..740
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 739
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 784
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 788
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 840
FT /ligand="methylcob(III)alamin"
FT /ligand_id="ChEBI:CHEBI:28115"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 924
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 1131
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
FT BINDING 1186..1187
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000256|PIRSR:PIRSR000381-2"
SQ SEQUENCE 1224 AA; 133932 MW; 0019842EED9D4B2F CRC64;
MGTMIQRHKL KEEDYRGSRF ADHSHPLLGN NDMLVLTQPD IIYTLHCAFL EAGSDIIETN
SFNANPISQA DYSAVELVHE LNVEACRLAR RAADEFSAKT PNKPRFVAGS IGPTNKTLSL
SPDVNRPGYR AVTFREVVDN YLVQLEGLRE GGVDLLLVET VFDTLNCKAA LFAISEIFER
TGWRVPVMVS GTVVDASGRT LSGQTTEAFW SSVCHLPELL SIGLNCALGS KQMRPFIEAM
ANVAESYVSV YPNAGLPNEF GQYDDSPEYM ATQIADFATS GFVNIVGGCC GTTPDHIKAI
AEAVQTISPR KRPTKKHELL LSGLEPLVVN HTTGFINIGE RTNVTGSKKF ARLIKEGNYD
EALSIARQQV ENGAQVIDVN VDEGMLDSEK VMKEFLNLIA SEPEISRVPI MIDSSKWSVI
ESGLQCVQGK GIVNSISLKE GDELFRERAR KILRYGAATV VMAFDEQGQA DNLQRRIEIC
QRAYNILVNE VGFPPEDIIF DPNVLTVATG IEEHNNYAVD FIESVRWIKE NLPHAKVSGG
ISNVSFSFRG NEPVREAMHA AFLYHAIRAG LDMGIVNAGQ LAIYEDIEPE LLVRVEDVLL
NRRADATERL VSFAETIATG GEKVEAKAAE WRNLPVAERL RHALIKGIVE HIEEDTEEAR
QLYPSPLQVI EGPLMDGMNA IGDLFAVGKM FLPQVVKSAR VMKRSVAHLI PFIEAEKAKN
KDTSAQAKVL LATVKGDVHD IGKNIVAVVL ACNNYEVIDI GVMMPCEKIL EAVEREKADL
LGLSGLITPS LDEMVHVAAE MERRGMKIPL LIGGATTSRM HTAVKIAPVY SGAVVQVLDA
SRSVPVVNSL LNPALSPKYI ADLKNEQAGL RESHAAAQAA RNYVSLADAR NNAAKVEPVA
VQPKKVGLTL FEDVAVAELR AYIDWTPLFM TWELHGRYPQ ILSDAKYGSE AQKLLNDANA
LLDRIELEKL LGVKGVVGIF PANSTGDDIA IYTDESRTKV LTTLHTLRQQ QEKANGEANV
ALADFIASAD SGVADYLGAF AVTTGLGIAK TLERFVAEHD DYHRILMQTV ADRLAEAFAE
MLHECVRREV WGYEEVCSKT SSCCACHAES ATTSQANHLE ELLAGNYQGI RPAPGYPACP
DHSEKAEIFT LLNAEVNTGI TLTENFAMNP AASVSGLYLA HPEARYFMLG KIGKDQVEDY
AQRKGINVAE AEKLLATSLN YQAG
//
