ID   SPCS_CAEEL              Reviewed;         481 AA.
AC   Q18953; B5U8M4;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   03-AUG-2022, entry version 136.
DE   RecName: Full=O-phosphoseryl-tRNA(Sec) selenium transferase;
DE            EC=2.9.1.2 {ECO:0000250|UniProtKB:Q9HD40};
DE   AltName: Full=Selenocysteine synthase;
DE            Short=Sec synthase;
DE   AltName: Full=Selenocysteinyl-tRNA(Sec) synthase;
DE   AltName: Full=Sep-tRNA:Sec-tRNA synthase;
DE            Short=SepSecS;
DE   AltName: Full=UGA suppressor tRNA-associated protein homolog;
GN   Name=secs-1; ORFNames=D1054.13;
OS   Caenorhabditis elegans.
OC   Eukaryota; Metazoa; Ecdysozoa; Nematoda; Chromadorea; Rhabditida;
OC   Rhabditina; Rhabditomorpha; Rhabditoidea; Rhabditidae; Peloderinae;
OC   Caenorhabditis.
OX   NCBI_TaxID=6239;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA], AND ALTERNATIVE SPLICING.
RC   STRAIN=Bristol N2;
RX   PubMed=9851916; DOI=10.1126/science.282.5396.2012;
RG   The C. elegans sequencing consortium;
RT   "Genome sequence of the nematode C. elegans: a platform for investigating
RT   biology.";
RL   Science 282:2012-2018(1998).
CC   -!- FUNCTION: Converts O-phosphoseryl-tRNA(Sec) to selenocysteinyl-
CC       tRNA(Sec) required for selenoprotein biosynthesis.
CC       {ECO:0000250|UniProtKB:Q9HD40}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=H2O + O-phospho-L-seryl-tRNA(Sec) + selenophosphate = L-
CC         selenocysteinyl-tRNA(Sec) + 2 phosphate; Xref=Rhea:RHEA:25041,
CC         Rhea:RHEA-COMP:9743, Rhea:RHEA-COMP:9947, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:16144, ChEBI:CHEBI:43474, ChEBI:CHEBI:78551,
CC         ChEBI:CHEBI:78573; EC=2.9.1.2;
CC         Evidence={ECO:0000250|UniProtKB:Q9HD40};
CC   -!- COFACTOR:
CC       Name=pyridoxal 5'-phosphate; Xref=ChEBI:CHEBI:597326;
CC         Evidence={ECO:0000250|UniProtKB:Q9HD40};
CC   -!- PATHWAY: Aminoacyl-tRNA biosynthesis; selenocysteinyl-tRNA(Sec)
CC       biosynthesis; selenocysteinyl-tRNA(Sec) from L-seryl-tRNA(Sec)
CC       (archaeal/eukaryal route): step 2/2. {ECO:0000250|UniProtKB:Q9HD40}.
CC   -!- SUBUNIT: Homotetramer formed by a catalytic dimer and a non-catalytic
CC       dimer serving as a binding platform that orients tRNASec for catalysis.
CC       Each tetramer binds the CCA ends of two tRNAs which point to the active
CC       sites of the catalytic dimer. {ECO:0000250|UniProtKB:Q9HD40}.
CC   -!- INTERACTION:
CC       Q18953; P03949: abl-1; NbExp=7; IntAct=EBI-318539, EBI-2315883;
CC       Q18953; Q18953: secs-1; NbExp=3; IntAct=EBI-318539, EBI-318539;
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250|UniProtKB:Q9HD40}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative splicing; Named isoforms=2;
CC       Name=a;
CC         IsoId=Q18953-1; Sequence=Displayed;
CC       Name=b;
CC         IsoId=Q18953-2; Sequence=VSP_038162;
CC   -!- SIMILARITY: Belongs to the SepSecS family. {ECO:0000305}.
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DR   EMBL; Z74030; CAA98446.1; -; Genomic_DNA.
DR   EMBL; Z74030; CAR64661.1; -; Genomic_DNA.
DR   PIR; T20309; T20309.
DR   RefSeq; NP_001129887.1; NM_001136415.1. [Q18953-2]
DR   RefSeq; NP_505761.1; NM_073360.3. [Q18953-1]
DR   AlphaFoldDB; Q18953; -.
DR   SMR; Q18953; -.
DR   BioGRID; 44527; 11.
DR   DIP; DIP-26886N; -.
DR   IntAct; Q18953; 9.
DR   MINT; Q18953; -.
DR   STRING; 6239.D1054.13b; -.
DR   EPD; Q18953; -.
DR   PaxDb; Q18953; -.
DR   PeptideAtlas; Q18953; -.
DR   EnsemblMetazoa; D1054.13a.1; D1054.13a.1; WBGene00008379. [Q18953-1]
DR   EnsemblMetazoa; D1054.13b.1; D1054.13b.1; WBGene00008379. [Q18953-2]
DR   GeneID; 179498; -.
DR   KEGG; cel:CELE_D1054.13; -.
DR   CTD; 179498; -.
DR   WormBase; D1054.13a; CE05531; WBGene00008379; secs-1. [Q18953-1]
DR   WormBase; D1054.13b; CE43036; WBGene00008379; secs-1. [Q18953-2]
DR   eggNOG; KOG3843; Eukaryota.
DR   GeneTree; ENSGT00390000007332; -.
DR   HOGENOM; CLU_022508_0_0_1; -.
DR   InParanoid; Q18953; -.
DR   OMA; HIINGAY; -.
DR   OrthoDB; 680116at2759; -.
DR   PhylomeDB; Q18953; -.
DR   UniPathway; UPA00906; UER00898.
DR   PRO; PR:Q18953; -.
DR   Proteomes; UP000001940; Chromosome V.
DR   Bgee; WBGene00008379; Expressed in germ line (C elegans) and 4 other tissues.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0042802; F:identical protein binding; IPI:IntAct.
DR   GO; GO:0098621; F:phosphoseryl-selenocysteinyl-tRNA selenium transferase activity; IEA:UniProtKB-EC.
DR   GO; GO:0000049; F:tRNA binding; IBA:GO_Central.
DR   GO; GO:0001514; P:selenocysteine incorporation; IBA:GO_Central.
DR   GO; GO:0097056; P:selenocysteinyl-tRNA(Sec) biosynthetic process; IEA:UniProtKB-UniPathway.
DR   Gene3D; 3.40.640.10; -; 1.
DR   InterPro; IPR015424; PyrdxlP-dep_Trfase.
DR   InterPro; IPR015421; PyrdxlP-dep_Trfase_major.
DR   InterPro; IPR019872; Sec-tRNA_Se_transferase.
DR   InterPro; IPR008829; SepSecS/SepCysS.
DR   PANTHER; PTHR12944; PTHR12944; 1.
DR   Pfam; PF05889; SepSecS; 1.
DR   PIRSF; PIRSF017689; SepSecS; 1.
DR   SUPFAM; SSF53383; SSF53383; 1.
DR   TIGRFAMs; TIGR03531; selenium_SpcS; 1.
PE   1: Evidence at protein level;
KW   Alternative splicing; Cytoplasm; Protein biosynthesis; Pyridoxal phosphate;
KW   Reference proteome; RNA-binding; Selenium; Transferase; tRNA-binding.
FT   CHAIN           1..481
FT                   /note="O-phosphoseryl-tRNA(Sec) selenium transferase"
FT                   /id="PRO_0000219880"
FT   REGION          1..36
FT                   /note="Tetramerization"
FT                   /evidence="ECO:0000250|UniProtKB:Q9HD40"
FT   REGION          90..100
FT                   /note="Phosphate loop (P-loop)"
FT                   /evidence="ECO:0000250|UniProtKB:Q9HD40"
FT   BINDING         69
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT                   /evidence="ECO:0000250|UniProtKB:Q9HD40"
FT   BINDING         91
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:Q9HD40"
FT   BINDING         92
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:Q9HD40"
FT   BINDING         99
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:Q9HD40"
FT   BINDING         306
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:Q9HD40"
FT   SITE            68
FT                   /note="May act as a substrate filter by repelling compounds
FT                   with a negatively charged alpha-carboxylate"
FT                   /evidence="ECO:0000250|UniProtKB:Q6P6M7"
FT   MOD_RES         277
FT                   /note="N6-(pyridoxal phosphate)lysine"
FT                   /evidence="ECO:0000250|UniProtKB:Q9HD40"
FT   VAR_SEQ         1
FT                   /note="M -> MSFEKLLMNLPGHTECACLPLCVDCQSRVDDCVSGRTARSEDM (in
FT                   isoform b)"
FT                   /evidence="ECO:0000305"
FT                   /id="VSP_038162"
SQ   SEQUENCE   481 AA;  53408 MW;  1EFFCD6F6B989FE6 CRC64;
     MKANFGKKEG EYSRLVSKSS NKLLNSLWEK KQIPEEGWSE HTLDLFLSWL SSHDTNNRVD
     MIPVGAGERE GRVLTPLVQR LHSNLTHGIG RSGNLLEIQP KALGSSMLAC LSNEFAKHAL
     HLLGLHAVKS CIVVPLCTGM SLSLCMTSWR RRRPKAKYVV WLRIDQKSSL KSIYHAGFEP
     IIVEPIRDRD SLITDVETVN RIIEQRGEEI LCVMTTTSCF APRSPDNVEA ISAICAAHDV
     PHLVNNAYGL QSEETIRKIA AAHECGRVDA VVQSLDKNFQ VPVGGAVIAA FKQNHIQSIA
     QSYPGRASSV PSRDLVLTLL YQGQSAFLEP FGKQKQMFLK MRRKLISFAE NIGECVYEVP
     ENEISSAMTL STIPPAKQTL FGSILFAKGI TGARVVTSSQ SKTTIEGCEF INFGSHTTEQ
     HGGYLNIACS VGMTDHELEE LFTRLTSSYA KFVRELAKED ERINSSGRRI PINESFDMEN
     D