ID   SERC_ECOLI              Reviewed;         362 AA.
AC   P23721; P78266;
DT   01-NOV-1991, integrated into UniProtKB/Swiss-Prot.
DT   23-JAN-2007, sequence version 4.
DT   02-SEP-2026, entry version 209.
DE   RecName: Full=Phosphoserine aminotransferase;
DE            EC=2.6.1.52;
DE   AltName: Full=Phosphohydroxythreonine aminotransferase;
DE            Short=PSAT;
GN   Name=serC; Synonyms=pdxC, pdxF; OrderedLocusNames=b0907, JW0890;
OS   Escherichia coli (strain K12).
OC   Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria;
OC   Enterobacterales; Enterobacteriaceae; Escherichia.
OX   NCBI_TaxID=83333;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=K12;
RX   PubMed=3518706; DOI=10.1042/bj2340049;
RA   Duncan K., Coggins J.R.;
RT   "The serC-aro A operon of Escherichia coli. A mixed function operon
RT   encoding enzymes from two different amino acid biosynthetic pathways.";
RL   Biochem. J. 234:49-57(1986).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=K12 / W3110 / ATCC 27325 / DSM 5911;
RX   PubMed=8905232; DOI=10.1093/dnares/3.3.137;
RA   Oshima T., Aiba H., Baba T., Fujita K., Hayashi K., Honjo A., Ikemoto K.,
RA   Inada T., Itoh T., Kajihara M., Kanai K., Kashimoto K., Kimura S.,
RA   Kitagawa M., Makino K., Masuda S., Miki T., Mizobuchi K., Mori H.,
RA   Motomura K., Nakamura Y., Nashimoto H., Nishio Y., Saito N., Sampei G.,
RA   Seki Y., Tagami H., Takemoto K., Wada C., Yamamoto Y., Yano M.,
RA   Horiuchi T.;
RT   "A 718-kb DNA sequence of the Escherichia coli K-12 genome corresponding to
RT   the 12.7-28.0 min region on the linkage map.";
RL   DNA Res. 3:137-155(1996).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=K12 / MG1655 / ATCC 47076;
RX   PubMed=9278503; DOI=10.1126/science.277.5331.1453;
RA   Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V.,
RA   Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F.,
RA   Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B.,
RA   Shao Y.;
RT   "The complete genome sequence of Escherichia coli K-12.";
RL   Science 277:1453-1462(1997).
RN   [4]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=K12 / W3110 / ATCC 27325 / DSM 5911;
RX   PubMed=16738553; DOI=10.1038/msb4100049;
RA   Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S.,
RA   Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T.;
RT   "Highly accurate genome sequences of Escherichia coli K-12 strains MG1655
RT   and W3110.";
RL   Mol. Syst. Biol. 2:E1-E5(2006).
RN   [5]
RP   PROTEIN SEQUENCE OF 2-13.
RC   STRAIN=K12 / EMG2;
RX   PubMed=9298646; DOI=10.1002/elps.1150180807;
RA   Link A.J., Robison K., Church G.M.;
RT   "Comparing the predicted and observed properties of proteins encoded in the
RT   genome of Escherichia coli K-12.";
RL   Electrophoresis 18:1259-1313(1997).
RN   [6]
RP   SIMILARITY TO RABBIT EPIP.
RX   PubMed=2682527; DOI=10.1093/nar/17.20.8379;
RA   van der Zel A., Lam H.-M., Winkler M.E.;
RT   "Extensive homology between the Escherichia coli K-12 SerC(PdxF)
RT   aminotransferase and a protein encoded by a progesterone-induced mRNA in
RT   rabbit and human endometria.";
RL   Nucleic Acids Res. 17:8379-8379(1989).
RN   [7]
RP   FUNCTION, AND PATHWAY.
RC   STRAIN=K12;
RX   PubMed=2121717; DOI=10.1128/jb.172.11.6518-6528.1990;
RA   Lam H.-M., Winkler M.E.;
RT   "Metabolic relationships between pyridoxine (vitamin B6) and serine
RT   biosynthesis in Escherichia coli K-12.";
RL   J. Bacteriol. 172:6518-6528(1990).
RN   [8]
RP   FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES, AND COFACTOR.
RX   PubMed=8706854; DOI=10.1016/0014-5793(96)00652-7;
RA   Drewke C., Klein M., Clade D., Arenz A., Mueller R., Leistner E.;
RT   "4-O-phosphoryl-L-threonine, a substrate of the pdxC(serC) gene product
RT   involved in vitamin B6 biosynthesis.";
RL   FEBS Lett. 390:179-182(1996).
RN   [9]
RP   X-RAY CRYSTALLOGRAPHY (2.3 ANGSTROMS) OF 3-362 IN COMPLEX WITH PLP AND
RP   SUBSTRATE ANALOG, SUBUNIT, CATALYTIC MECHANISM, AND PYRIDOXAL PHOSPHATE AT
RP   LYS-198.
RX   PubMed=10024454; DOI=10.1006/jmbi.1998.2506;
RA   Hester G., Stark W., Moser M., Kallen J., Markovic-Housley Z.,
RA   Jansonius J.N.;
RT   "Crystal structure of phosphoserine aminotransferase from Escherichia coli
RT   at 2.3-A resolution: comparison of the unligated enzyme and a complex with
RT   alpha-methyl-L-glutamate.";
RL   J. Mol. Biol. 286:829-850(1999).
CC   -!- FUNCTION: Catalyzes the reversible conversion of 3-
CC       phosphohydroxypyruvate to phosphoserine and of 3-hydroxy-2-oxo-4-
CC       phosphonooxybutanoate to phosphohydroxythreonine. Is involved in both
CC       pyridoxine and serine biosynthesis. {ECO:0000269|PubMed:2121717,
CC       ECO:0000269|PubMed:8706854}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=O-phospho-L-serine + 2-oxoglutarate = 3-phosphooxypyruvate +
CC         L-glutamate; Xref=Rhea:RHEA:14329, ChEBI:CHEBI:16810,
CC         ChEBI:CHEBI:18110, ChEBI:CHEBI:29985, ChEBI:CHEBI:57524; EC=2.6.1.52;
CC         Evidence={ECO:0000269|PubMed:8706854};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=4-(phosphooxy)-L-threonine + 2-oxoglutarate = (R)-3-hydroxy-2-
CC         oxo-4-phosphooxybutanoate + L-glutamate; Xref=Rhea:RHEA:16573,
CC         ChEBI:CHEBI:16810, ChEBI:CHEBI:29985, ChEBI:CHEBI:58452,
CC         ChEBI:CHEBI:58538; EC=2.6.1.52;
CC         Evidence={ECO:0000269|PubMed:8706854};
CC   -!- COFACTOR:
CC       Name=pyridoxal 5'-phosphate; Xref=ChEBI:CHEBI:597326;
CC         Evidence={ECO:0000269|PubMed:8706854};
CC       Note=Binds 1 pyridoxal phosphate per subunit.
CC       {ECO:0000269|PubMed:8706854};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         KM=15 uM for 3-phosphonooxypyruvate {ECO:0000269|PubMed:8706854};
CC         KM=17 uM for O(3)-phospho-L-serine {ECO:0000269|PubMed:8706854};
CC         KM=110 uM for 4-phosphonooxy-L-threonine
CC         {ECO:0000269|PubMed:8706854};
CC         Vmax=45 nmol/sec/mg enzyme with 3-phosphonooxypyruvate as substrate
CC         {ECO:0000269|PubMed:8706854};
CC         Vmax=9.9 nmol/sec/mg enzyme with O(3)-phospho-L-serine as substrate
CC         {ECO:0000269|PubMed:8706854};
CC         Vmax=3.8 nmol/sec/mg enzyme with 4-phosphonooxy-L-threonine as
CC         substrate {ECO:0000269|PubMed:8706854};
CC         Note=No activity could be observed with non-phosphorylated
CC         substrates.;
CC       pH dependence:
CC         Optimum pH is 7.5-8.8. {ECO:0000269|PubMed:8706854};
CC   -!- PATHWAY: Amino-acid biosynthesis; L-serine biosynthesis; L-serine from
CC       3-phospho-D-glycerate: step 2/3. {ECO:0000269|PubMed:2121717}.
CC   -!- PATHWAY: Cofactor biosynthesis; pyridoxine 5'-phosphate biosynthesis;
CC       pyridoxine 5'-phosphate from D-erythrose 4-phosphate: step 3/5.
CC       {ECO:0000269|PubMed:2121717}.
CC   -!- SUBUNIT: Homodimer. {ECO:0000269|PubMed:10024454}.
CC   -!- INTERACTION:
CC       P23721; P0A6Y8: dnaK; NbExp=2; IntAct=EBI-557952, EBI-542092;
CC       P23721; P14081: selB; NbExp=3; IntAct=EBI-557952, EBI-551705;
CC   -!- SUBCELLULAR LOCATION: Cytoplasm.
CC   -!- SIMILARITY: Belongs to the class-V pyridoxal-phosphate-dependent
CC       aminotransferase family. SerC subfamily. {ECO:0000305}.
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DR   EMBL; U00096; AAC73993.1; -; Genomic_DNA.
DR   EMBL; AP009048; BAA35642.1; -; Genomic_DNA.
DR   PIR; B64830; B64830.
DR   RefSeq; NP_415427.1; NC_000913.3.
DR   RefSeq; WP_000057138.1; NZ_CP009789.1.
DR   PDB; 1BJN; X-ray; 2.30 A; A/B=3-362.
DR   PDB; 1BJO; X-ray; 2.80 A; A/B=3-362.
DR   AlphaFoldDB; P23721; -.
DR   SMR; P23721; -.
DR   BioGRID; 4260006; 38.
DR   DIP; DIP-2896N; -.
DR   FunCoup; P23721; 773.
DR   IntAct; P23721; 9.
DR   STRING; 511145.b0907; -.
DR   jPOST; P23721; -.
DR   PaxDb; 511145-b0907; -.
DR   EnsemblBacteria; AAC73993; AAC73993; b0907.
DR   GeneID; 945527; -.
DR   KEGG; ecj:JW0890; -.
DR   KEGG; eco:b0907; -.
DR   KEGG; ecoc:C3026_05595; -.
DR   PATRIC; fig|1411691.4.peg.1369; -.
DR   EchoBASE; EB0939; -.
DR   eggNOG; COG1932; Bacteria.
DR   HOGENOM; CLU_034866_0_2_6; -.
DR   InParanoid; P23721; -.
DR   OMA; AFVYFCD; -.
DR   OrthoDB; 9809412at2; -.
DR   PhylomeDB; P23721; -.
DR   BioCyc; EcoCyc:PSERTRANSAM-MONOMER; -.
DR   BioCyc; MetaCyc:PSERTRANSAM-MONOMER; -.
DR   BRENDA; 2.6.1.52; 2026.
DR   SABIO-RK; P23721; -.
DR   UniPathway; UPA00135; UER00197.
DR   UniPathway; UPA00244; UER00311.
DR   EvolutionaryTrace; P23721; -.
DR   PRO; PR:P23721; -.
DR   Proteomes; UP000000625; Chromosome.
DR   AbasyAtlas; P23721; -.
DR   GO; GO:0005829; C:cytosol; IDA:EcoCyc.
DR   GO; GO:0004648; F:O-phospho-L-serine:2-oxoglutarate transaminase activity; IDA:EcoCyc.
DR   GO; GO:0042803; F:protein homodimerization activity; IDA:EcoCyc.
DR   GO; GO:0030170; F:pyridoxal phosphate binding; IDA:EcoCyc.
DR   GO; GO:0006564; P:L-serine biosynthetic process; IMP:EcoCyc.
DR   GO; GO:0006563; P:L-serine metabolic process; IGI:UniProtKB.
DR   GO; GO:0042823; P:pyridoxal 5'-phosphate biosynthetic process; IMP:EcoCyc.
DR   GO; GO:0008615; P:pyridoxine biosynthetic process; IEA:UniProtKB-UniRule.
DR   CDD; cd00611; PSAT_like; 1.
DR   FunFam; 3.40.640.10:FF:000010; Phosphoserine aminotransferase; 1.
DR   FunFam; 3.90.1150.10:FF:000006; Phosphoserine aminotransferase; 1.
DR   Gene3D; 3.90.1150.10; Aspartate Aminotransferase, domain 1; 1.
DR   Gene3D; 3.40.640.10; Type I PLP-dependent aspartate aminotransferase-like (Major domain); 1.
DR   HAMAP; MF_00160; SerC_aminotrans_5; 1.
DR   InterPro; IPR000192; Aminotrans_V_dom.
DR   InterPro; IPR020578; Aminotrans_V_PyrdxlP_BS.
DR   InterPro; IPR022278; Pser_aminoTfrase.
DR   InterPro; IPR015424; PyrdxlP-dep_Trfase.
DR   InterPro; IPR015421; PyrdxlP-dep_Trfase_major.
DR   InterPro; IPR015422; PyrdxlP-dep_Trfase_small.
DR   NCBIfam; NF003764; PRK05355.1; 1.
DR   NCBIfam; TIGR01364; serC_1; 1.
DR   PANTHER; PTHR43247; PHOSPHOSERINE AMINOTRANSFERASE; 1.
DR   PANTHER; PTHR43247:SF1; PHOSPHOSERINE AMINOTRANSFERASE; 1.
DR   Pfam; PF00266; Aminotran_5; 1.
DR   PIRSF; PIRSF000525; SerC; 1.
DR   SUPFAM; SSF53383; PLP-dependent transferases; 1.
DR   PROSITE; PS00595; AA_TRANSFER_CLASS_5; 1.
DR   PDBsum; 1BJN; -.
DR   PDBsum; 1BJO; -.
PE   1: Evidence at protein level;
KW   3D-structure; Amino-acid biosynthesis; Aminotransferase; Cytoplasm;
KW   Direct protein sequencing; Pyridoxal phosphate; Pyridoxine biosynthesis;
KW   Reference proteome; Serine biosynthesis; Transferase.
FT   INIT_MET        1
FT                   /note="Removed"
FT                   /evidence="ECO:0000269|PubMed:9298646"
FT   CHAIN           2..362
FT                   /note="Phosphoserine aminotransferase"
FT                   /id="PRO_0000150167"
FT   BINDING         9
FT                   /ligand="L-glutamate"
FT                   /ligand_id="ChEBI:CHEBI:29985"
FT   BINDING         42
FT                   /ligand="L-glutamate"
FT                   /ligand_id="ChEBI:CHEBI:29985"
FT   BINDING         76..77
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   BINDING         102
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   BINDING         153
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   BINDING         174
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   BINDING         197
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   BINDING         239..240
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   MOD_RES         198
FT                   /note="N6-(pyridoxal phosphate)lysine"
FT   CONFLICT        293
FT                   /note="A -> R (in Ref. 1; no nucleotide entry)"
FT                   /evidence="ECO:0000305"
FT   STRAND          9..11
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           16..24
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          26..28
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           29..31
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          32..34
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           36..38
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           44..61
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          67..74
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           75..87
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          93..100
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           101..110
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   TURN            111..113
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          114..120
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          122..125
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          128..131
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           134..136
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          146..148
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          150..152
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   TURN            153..156
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           161..163
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          171..174
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   TURN            176..180
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           186..188
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          190..195
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   TURN            196..200
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          206..211
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           212..214
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           224..226
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           228..233
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   TURN            234..236
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           243..258
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           261..282
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          284..287
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           292..294
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          297..306
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           307..309
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           310..319
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   TURN            329..331
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   STRAND          333..337
FT                   /evidence="ECO:0007829|PDB:1BJN"
FT   HELIX           344..361
FT                   /evidence="ECO:0007829|PDB:1BJN"
SQ   SEQUENCE   362 AA;  39783 MW;  F6A58CBF9FA22BC9 CRC64;
     MAQIFNFSSG PAMLPAEVLK QAQQELRDWN GLGTSVMEVS HRGKEFIQVA EEAEKDFRDL
     LNVPSNYKVL FCHGGGRGQF AAVPLNILGD KTTADYVDAG YWAASAIKEA KKYCTPNVFD
     AKVTVDGLRA VKPMREWQLS DNAAYMHYCP NETIDGIAID ETPDFGADVV VAADFSSTIL
     SRPIDVSRYG VIYAGAQKNI GPAGLTIVIV REDLLGKANI ACPSILDYSI LNDNGSMFNT
     PPTFAWYLSG LVFKWLKANG GVAEMDKINQ QKAELLYGVI DNSDFYRNDV AKANRSRMNV
     PFQLADSALD KLFLEESFAA GLHALKGHRV VGGMRASIYN AMPLEGVKAL TDFMVEFERR
     HG
//