ID   CBS_RABIT               Reviewed;         551 AA.
AC   Q9N0V7;
DT   28-NOV-2006, integrated into UniProtKB/Swiss-Prot.
DT   23-JAN-2007, sequence version 3.
DT   03-AUG-2022, entry version 102.
DE   RecName: Full=Cystathionine beta-synthase {ECO:0000305};
DE            EC=4.2.1.22 {ECO:0000250|UniProtKB:P35520};
DE   AltName: Full=Beta-thionase;
DE   AltName: Full=Serine sulfhydrase;
GN   Name=CBS;
OS   Oryctolagus cuniculus (Rabbit).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Euarchontoglires; Glires; Lagomorpha; Leporidae; Oryctolagus.
OX   NCBI_TaxID=9986;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Liver;
RA   Fujiwara K., Matsuda J., Tokunaga T.;
RT   "Cloning and characterization of a cDNA clone of rabbit cystathionine beta
RT   synthase.";
RL   Submitted (MAR-2000) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Hydro-lyase catalyzing the first step of the transsulfuration
CC       pathway, where the hydroxyl group of L-serine is displaced by L-
CC       homocysteine in a beta-replacement reaction to form L-cystathionine,
CC       the precursor of L-cysteine. This catabolic route allows the
CC       elimination of L-methionine and the toxic metabolite L-homocysteine (By
CC       similarity). Also involved in the production of hydrogen sulfide, a
CC       gasotransmitter with signaling and cytoprotective effects on neurons
CC       (By similarity). {ECO:0000250|UniProtKB:P32232,
CC       ECO:0000250|UniProtKB:P35520}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-homocysteine + L-serine = H2O + L,L-cystathionine;
CC         Xref=Rhea:RHEA:10112, ChEBI:CHEBI:15377, ChEBI:CHEBI:33384,
CC         ChEBI:CHEBI:58161, ChEBI:CHEBI:58199; EC=4.2.1.22;
CC         Evidence={ECO:0000250|UniProtKB:P35520};
CC   -!- COFACTOR:
CC       Name=pyridoxal 5'-phosphate; Xref=ChEBI:CHEBI:597326;
CC         Evidence={ECO:0000250|UniProtKB:P35520};
CC   -!- ACTIVITY REGULATION: Allosterically activated by S-adenosyl-
CC       methionine/AdoMet. Activated by S-adenosylhomocysteine/AdoHcy. Binds
CC       non-covalently to a heme group that may control the redox sensitivity
CC       of the enzyme. {ECO:0000250|UniProtKB:P35520}.
CC   -!- PATHWAY: Amino-acid biosynthesis; L-cysteine biosynthesis; L-cysteine
CC       from L-homocysteine and L-serine: step 1/2.
CC       {ECO:0000250|UniProtKB:P35520}.
CC   -!- SUBUNIT: Homotetramer. {ECO:0000250|UniProtKB:P35520}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250|UniProtKB:P35520}. Nucleus
CC       {ECO:0000250|UniProtKB:P35520}.
CC   -!- SIMILARITY: Belongs to the cysteine synthase/cystathionine beta-
CC       synthase family. {ECO:0000305}.
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DR   EMBL; AF248039; AAF64226.1; -; mRNA.
DR   RefSeq; NP_001075551.1; NM_001082082.2.
DR   AlphaFoldDB; Q9N0V7; -.
DR   SMR; Q9N0V7; -.
DR   STRING; 9986.ENSOCUP00000015163; -.
DR   PRIDE; Q9N0V7; -.
DR   GeneID; 100008766; -.
DR   KEGG; ocu:100008766; -.
DR   CTD; 875; -.
DR   eggNOG; KOG1252; Eukaryota.
DR   InParanoid; Q9N0V7; -.
DR   OrthoDB; 1016546at2759; -.
DR   UniPathway; UPA00136; UER00201.
DR   Proteomes; UP000001811; Unplaced.
DR   GO; GO:0005737; C:cytoplasm; ISS:UniProtKB.
DR   GO; GO:0005634; C:nucleus; ISS:UniProtKB.
DR   GO; GO:0004122; F:cystathionine beta-synthase activity; ISS:UniProtKB.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0042803; F:protein homodimerization activity; ISS:UniProtKB.
DR   GO; GO:0030170; F:pyridoxal phosphate binding; ISS:UniProtKB.
DR   GO; GO:0006535; P:cysteine biosynthetic process from serine; IEA:InterPro.
DR   GO; GO:0019343; P:cysteine biosynthetic process via cystathionine; IEA:InterPro.
DR   GO; GO:0043418; P:homocysteine catabolic process; ISS:UniProtKB.
DR   GO; GO:0050667; P:homocysteine metabolic process; ISS:UniProtKB.
DR   GO; GO:0070814; P:hydrogen sulfide biosynthetic process; ISS:UniProtKB.
DR   GO; GO:0006563; P:L-serine metabolic process; ISS:UniProtKB.
DR   CDD; cd04608; CBS_pair_CBS; 1.
DR   Gene3D; 3.10.580.10; -; 1.
DR   Gene3D; 3.40.50.1100; -; 2.
DR   InterPro; IPR046353; CBS_C.
DR   InterPro; IPR000644; CBS_dom.
DR   InterPro; IPR046342; CBS_dom_sf.
DR   InterPro; IPR005857; Cysta_beta_synth.
DR   InterPro; IPR001216; P-phosphate_BS.
DR   InterPro; IPR001926; PLP-dep.
DR   InterPro; IPR036052; Trypto_synt_PLP_dependent.
DR   Pfam; PF00571; CBS; 1.
DR   Pfam; PF00291; PALP; 1.
DR   SMART; SM00116; CBS; 1.
DR   SUPFAM; SSF53686; SSF53686; 1.
DR   SUPFAM; SSF54631; SSF54631; 1.
DR   TIGRFAMs; TIGR01137; cysta_beta; 1.
DR   PROSITE; PS51371; CBS; 1.
DR   PROSITE; PS00901; CYS_SYNTHASE; 1.
PE   2: Evidence at transcript level;
KW   Amino-acid biosynthesis; CBS domain; Cysteine biosynthesis; Cytoplasm;
KW   Heme; Iron; Isopeptide bond; Lyase; Metal-binding; Nucleus; Phosphoprotein;
KW   Pyridoxal phosphate; Reference proteome; Ubl conjugation.
FT   CHAIN           1..551
FT                   /note="Cystathionine beta-synthase"
FT                   /id="PRO_0000263004"
FT   DOMAIN          418..476
FT                   /note="CBS"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00703"
FT   REGION          1..41
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   BINDING         52
FT                   /ligand="heme"
FT                   /ligand_id="ChEBI:CHEBI:30413"
FT                   /ligand_part="Fe"
FT                   /ligand_part_id="ChEBI:CHEBI:18248"
FT                   /note="axial binding residue"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
FT   BINDING         65
FT                   /ligand="heme"
FT                   /ligand_id="ChEBI:CHEBI:30413"
FT                   /ligand_part="Fe"
FT                   /ligand_part_id="ChEBI:CHEBI:18248"
FT                   /note="axial binding residue"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
FT   BINDING         149
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
FT   BINDING         256..260
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
FT   BINDING         349
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
FT   MOD_RES         27
FT                   /note="Phosphoserine"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
FT   MOD_RES         119
FT                   /note="N6-(pyridoxal phosphate)lysine"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
FT   MOD_RES         199
FT                   /note="Phosphoserine"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
FT   CROSSLNK        211
FT                   /note="Glycyl lysine isopeptide (Lys-Gly) (interchain with
FT                   G-Cter in SUMO)"
FT                   /evidence="ECO:0000250|UniProtKB:P35520"
SQ   SEQUENCE   551 AA;  60212 MW;  AE14CC7EDA6BA2AD CRC64;
     MPSETAQAGE GPAGCPHLSG AQGSDRSLDQ RPPGNKDAPE RVWIRPDVPS RCTWELGRPV
     ADSPHQHAAL AKSPKILPDI LQKIGDTPMV RINKIGKNFG LKCELLAKCE FFNAGGSVKD
     RISLRMIEDA ERAGTLRPGD TIIEPTSGNT GIGLALAAAV KGYRCIIVMP EKMSLEKVDV
     LRALGAEIVR TPTNARFDSP ESHVGVAWRL KQEIPNSHIL DQYRNASNPL AHYDTTAEEI
     LQQCDGKLDM LVASAGTGGT ITGIARKLKE KCPGCQIIGV DPEGSILAEP EELNQTEVTA
     YEVEGIGYDF IPTVLDRTVV DRWFKSTDKE AFAFARMLIA QEGLLCGGSA GSAVAVAVKA
     AQELQEGQRC VVILPDSVRN YMSKFLSDRW MLQKGFLEEE ELSVKRPWWW HLRVQELSLS
     VPLTVLPGVT CSDTIDILRG KGFDQAPVVD ETGEILGMVT LGNMLSSLLA GKVQPSDQVC
     KVLYKQFKQI RLTDTLGALS HILEMDHFAL VVHEQIQYGG DEQPSKRQTV FGVVTAMDLL
     HFVASRGQDQ Q