ID   CYSK_BUCAI              Reviewed;         315 AA.
AC   P57171;
DT   01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
DT   01-DEC-2000, sequence version 1.
DT   03-AUG-2022, entry version 119.
DE   RecName: Full=Cysteine synthase;
DE            Short=CSase;
DE            EC=2.5.1.47;
DE   AltName: Full=O-acetylserine (thiol)-lyase;
DE            Short=OAS-TL;
DE   AltName: Full=O-acetylserine sulfhydrylase;
GN   Name=cysK; OrderedLocusNames=BU066;
OS   Buchnera aphidicola subsp. Acyrthosiphon pisum (strain APS) (Acyrthosiphon
OS   pisum symbiotic bacterium).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=107806;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=APS;
RX   PubMed=10993077; DOI=10.1038/35024074;
RA   Shigenobu S., Watanabe H., Hattori M., Sakaki Y., Ishikawa H.;
RT   "Genome sequence of the endocellular bacterial symbiont of aphids Buchnera
RT   sp. APS.";
RL   Nature 407:81-86(2000).
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=hydrogen sulfide + O-acetyl-L-serine = acetate + L-cysteine;
CC         Xref=Rhea:RHEA:14829, ChEBI:CHEBI:29919, ChEBI:CHEBI:30089,
CC         ChEBI:CHEBI:35235, ChEBI:CHEBI:58340; EC=2.5.1.47;
CC   -!- COFACTOR:
CC       Name=pyridoxal 5'-phosphate; Xref=ChEBI:CHEBI:597326;
CC         Evidence={ECO:0000250};
CC   -!- PATHWAY: Amino-acid biosynthesis; L-cysteine biosynthesis; L-cysteine
CC       from L-serine: step 2/2.
CC   -!- SUBUNIT: Homodimer. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the cysteine synthase/cystathionine beta-
CC       synthase family. {ECO:0000305}.
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DR   EMBL; BA000003; BAB12789.1; -; Genomic_DNA.
DR   RefSeq; NP_239903.1; NC_002528.1.
DR   RefSeq; WP_010895923.1; NC_002528.1.
DR   AlphaFoldDB; P57171; -.
DR   SMR; P57171; -.
DR   STRING; 107806.10038754; -.
DR   PRIDE; P57171; -.
DR   EnsemblBacteria; BAB12789; BAB12789; BAB12789.
DR   KEGG; buc:BU066; -.
DR   PATRIC; fig|107806.10.peg.75; -.
DR   eggNOG; COG0031; Bacteria.
DR   HOGENOM; CLU_021018_1_2_6; -.
DR   OMA; FWDSGER; -.
DR   UniPathway; UPA00136; UER00200.
DR   Proteomes; UP000001806; Chromosome.
DR   GO; GO:0004124; F:cysteine synthase activity; IEA:UniProtKB-EC.
DR   GO; GO:0006535; P:cysteine biosynthetic process from serine; IEA:InterPro.
DR   Gene3D; 3.40.50.1100; -; 2.
DR   InterPro; IPR005856; Cys_synth.
DR   InterPro; IPR005859; CysK.
DR   InterPro; IPR001216; P-phosphate_BS.
DR   InterPro; IPR001926; PLP-dep.
DR   InterPro; IPR036052; Trypto_synt_PLP_dependent.
DR   Pfam; PF00291; PALP; 1.
DR   SUPFAM; SSF53686; SSF53686; 1.
DR   TIGRFAMs; TIGR01139; cysK; 1.
DR   TIGRFAMs; TIGR01136; cysKM; 1.
DR   PROSITE; PS00901; CYS_SYNTHASE; 1.
PE   3: Inferred from homology;
KW   Allosteric enzyme; Amino-acid biosynthesis; Cysteine biosynthesis;
KW   Pyridoxal phosphate; Reference proteome; Transferase.
FT   CHAIN           1..315
FT                   /note="Cysteine synthase"
FT                   /id="PRO_0000167083"
FT   BINDING         8
FT                   /ligand="hydrogen sulfide"
FT                   /ligand_id="ChEBI:CHEBI:29919"
FT                   /ligand_note="allosteric inhibitor; ligand shared between
FT                   dimeric partners"
FT                   /evidence="ECO:0000250|UniProtKB:P0A1E3"
FT   BINDING         35
FT                   /ligand="hydrogen sulfide"
FT                   /ligand_id="ChEBI:CHEBI:29919"
FT                   /ligand_note="allosteric inhibitor; ligand shared between
FT                   dimeric partners"
FT                   /note="in other chain"
FT                   /evidence="ECO:0000250|UniProtKB:P0A1E3"
FT   BINDING         72
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT                   /evidence="ECO:0000250"
FT   BINDING         177..181
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT                   /evidence="ECO:0000250"
FT   BINDING         269
FT                   /ligand="hydrogen sulfide"
FT                   /ligand_id="ChEBI:CHEBI:29919"
FT                   /ligand_note="allosteric inhibitor; ligand shared between
FT                   dimeric partners"
FT                   /note="in other chain"
FT                   /evidence="ECO:0000250|UniProtKB:P0A1E3"
FT   BINDING         273
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         42
FT                   /note="N6-(pyridoxal phosphate)lysine"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   315 AA;  34430 MW;  84D371238D4238FF CRC64;
     MSKIYQDNSL TIGNTPLVRL NRIGNGNILV KIESRNPSFS VKCRIGANMI WHAEKNNNIN
     KNVKLIEATS GNTGIALAYV AASRNYRLTL TMPETMSIER KKILKSLGAE LILTDGRYGM
     KGAISKANDI ISRNPSKYFL LKQFENPANP EIHQITTGPE IWNDTNGNLD ILISAVGTGG
     TITGITRYIK KIKRKKNLIS IAVEPSESPV ITQFLAGKAI EPGPHKIQGI GPGFIPKNLD
     LTIIDQVITV SSEEAILTAK ELMKKEGILA GISSGAALYA AIKIQQQKKF SDKKIVVILP
     SSGERYLSTE LFSEL