ID TDT_AMBME Reviewed; 510 AA.
AC O57486; Q800C6;
DT 15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT 15-AUG-2003, sequence version 2.
DT 22-FEB-2023, entry version 106.
DE RecName: Full=DNA nucleotidylexotransferase;
DE EC=2.7.7.31;
DE AltName: Full=Terminal addition enzyme;
DE AltName: Full=Terminal deoxynucleotidyltransferase;
DE Short=Terminal transferase;
GN Name=DNTT; Synonyms=TDT;
OS Ambystoma mexicanum (Axolotl).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Amphibia;
OC Batrachia; Caudata; Salamandroidea; Ambystomatidae; Ambystoma.
OX NCBI_TaxID=8296;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 1 AND 2).
RX PubMed=15146297; DOI=10.1007/s00251-004-0681-2;
RA Golub R., Andre S., Hassanin A., Affaticati P., Larijani M., Fellah J.S.;
RT "Early expression of two TdT isoforms in the hematopoietic system of the
RT Mexican axolotl. Implications for the evolutionary origin of the N-
RT nucleotide addition.";
RL Immunogenetics 56:204-213(2004).
CC -!- FUNCTION: Template-independent DNA polymerase which catalyzes the
CC random addition of deoxynucleoside 5'-triphosphate to the 3'-end of a
CC DNA initiator. One of the in vivo functions of this enzyme is the
CC addition of nucleotides at the junction (N region) of rearranged Ig
CC heavy chain and T-cell receptor gene segments during the maturation of
CC B- and T-cells. {ECO:0000250|UniProtKB:P09838}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) =
CC diphosphate + DNA(n+1); Xref=Rhea:RHEA:22508, Rhea:RHEA-COMP:17339,
CC Rhea:RHEA-COMP:17340, ChEBI:CHEBI:33019, ChEBI:CHEBI:61560,
CC ChEBI:CHEBI:173112; EC=2.7.7.31;
CC Evidence={ECO:0000250|UniProtKB:P09838};
CC -!- COFACTOR:
CC Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC Evidence={ECO:0000250|UniProtKB:P09838};
CC Note=Can also utilize other divalent cations, such as Mn(2+) and Co(2+)
CC (in vitro). {ECO:0000250|UniProtKB:P09838};
CC -!- SUBCELLULAR LOCATION: Nucleus {ECO:0000250|UniProtKB:P04053}.
CC -!- ALTERNATIVE PRODUCTS:
CC Event=Alternative splicing; Named isoforms=2;
CC Name=1;
CC IsoId=O57486-1; Sequence=Displayed;
CC Name=2;
CC IsoId=O57486-2; Sequence=VSP_007952;
CC -!- SIMILARITY: Belongs to the DNA polymerase type-X family. {ECO:0000305}.
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DR EMBL; AF039209; AAB92673.2; -; mRNA.
DR EMBL; AY248700; AAO92254.1; -; mRNA.
DR AlphaFoldDB; O57486; -.
DR SMR; O57486; -.
DR GO; GO:0005634; C:nucleus; ISS:UniProtKB.
DR GO; GO:0003677; F:DNA binding; IEA:InterPro.
DR GO; GO:0003912; F:DNA nucleotidylexotransferase activity; ISS:UniProtKB.
DR GO; GO:0003887; F:DNA-directed DNA polymerase activity; IEA:InterPro.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0006259; P:DNA metabolic process; ISS:UniProtKB.
DR GO; GO:0006304; P:DNA modification; IEA:UniProtKB-KW.
DR GO; GO:0006281; P:DNA repair; IEA:InterPro.
DR CDD; cd00141; NT_POLXc; 1.
DR Gene3D; 1.10.150.20; 5' to 3' exonuclease, C-terminal subdomain; 1.
DR Gene3D; 3.30.460.10; Beta Polymerase, domain 2; 1.
DR Gene3D; 3.40.50.10190; BRCT domain; 1.
DR Gene3D; 1.10.150.110; DNA polymerase beta, N-terminal domain-like; 1.
DR Gene3D; 3.30.210.10; DNA polymerase, thumb domain; 1.
DR InterPro; IPR001357; BRCT_dom.
DR InterPro; IPR036420; BRCT_dom_sf.
DR InterPro; IPR002054; DNA-dir_DNA_pol_X.
DR InterPro; IPR019843; DNA_pol-X_BS.
DR InterPro; IPR010996; DNA_pol_b-like_N.
DR InterPro; IPR028207; DNA_pol_B_palm_palm.
DR InterPro; IPR018944; DNA_pol_lambd_fingers_domain.
DR InterPro; IPR027421; DNA_pol_lamdba_lyase_dom_sf.
DR InterPro; IPR037160; DNA_Pol_thumb_sf.
DR InterPro; IPR022312; DNA_pol_X.
DR InterPro; IPR043519; NT_sf.
DR InterPro; IPR029398; PolB_thumb.
DR InterPro; IPR027292; TdT.
DR InterPro; IPR001726; TdT/Mu.
DR PANTHER; PTHR11276:SF21; DNA NUCLEOTIDYLEXOTRANSFERASE; 1.
DR PANTHER; PTHR11276; DNA POLYMERASE TYPE-X FAMILY MEMBER; 1.
DR Pfam; PF00533; BRCT; 1.
DR Pfam; PF14792; DNA_pol_B_palm; 1.
DR Pfam; PF14791; DNA_pol_B_thumb; 1.
DR Pfam; PF10391; DNA_pol_lambd_f; 1.
DR Pfam; PF14716; HHH_8; 1.
DR PIRSF; PIRSF000817; DNA_NT; 1.
DR PIRSF; PIRSF501175; TDT; 1.
DR PRINTS; PR00869; DNAPOLX.
DR PRINTS; PR00871; DNAPOLXTDT.
DR SMART; SM00292; BRCT; 1.
DR SMART; SM00483; POLXc; 1.
DR SUPFAM; SSF52113; BRCT domain; 1.
DR SUPFAM; SSF47802; DNA polymerase beta, N-terminal domain-like; 1.
DR SUPFAM; SSF81301; Nucleotidyltransferase; 1.
DR SUPFAM; SSF81585; PsbU/PolX domain-like; 1.
DR PROSITE; PS50172; BRCT; 1.
DR PROSITE; PS00522; DNA_POLYMERASE_X; 1.
PE 2: Evidence at transcript level;
KW Alternative splicing; Magnesium; Metal-binding; Nucleotidyltransferase;
KW Nucleus; Terminal addition; Transferase.
FT CHAIN 1..510
FT /note="DNA nucleotidylexotransferase"
FT /id="PRO_0000218794"
FT DOMAIN 27..124
FT /note="BRCT"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00033"
FT REGION 254..258
FT /note="Involved in DNA binding"
FT /evidence="ECO:0000250|UniProtKB:P09838"
FT MOTIF 11..17
FT /note="Nuclear localization signal"
FT /evidence="ECO:0000250|UniProtKB:P06526"
FT BINDING 329..334
FT /ligand="a 2'-deoxyribonucleoside 5'-triphosphate"
FT /ligand_id="ChEBI:CHEBI:61560"
FT /evidence="ECO:0000250|UniProtKB:P09838"
FT BINDING 338..341
FT /ligand="a 2'-deoxyribonucleoside 5'-triphosphate"
FT /ligand_id="ChEBI:CHEBI:61560"
FT /evidence="ECO:0000250|UniProtKB:P09838"
FT BINDING 339
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:P09838"
FT BINDING 341
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:P09838"
FT BINDING 434
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:P09838"
FT BINDING 449..450
FT /ligand="a 2'-deoxyribonucleoside 5'-triphosphate"
FT /ligand_id="ChEBI:CHEBI:61560"
FT /evidence="ECO:0000250|UniProtKB:P09838"
FT VAR_SEQ 166..222
FT /note="Missing (in isoform 2)"
FT /evidence="ECO:0000303|PubMed:15146297"
FT /id="VSP_007952"
SQ SEQUENCE 510 AA; 58244 MW; BA83394777EFA6D0 CRC64;
MYAFPTTRIA PRRKQPKCIK PPKCTSKYDI KFKDIAIYIL ERKMGASRRY FLMELARKKG
FRVEPDLSEY VTHVVSEKNS GAEVLEWLQA KKAGSIPNVA ILDISWFTDC MGAGQPVEIE
RKHRLTLQKI CVCKSPSPVV PSRVGVSQYA CQRKTTLDNK NTLFTDAFEI LAENYEFREN
ERSCLSFRQA ASVLKSLTFT IAGMADVDGL PGFGDHIRAV IEDLIEDGES SKVSEVLNDE
VYRSLKLFTT IFGVGLRTAE KWHRLGIRTL EEIKSNENLK FSKMQIAGLQ HYEDILGGVR
KAEADAVAMV VRDAVWTFLP DAVVTLTGGF RRGNKTGHDV DMLITSPIQG KEKELLHKVI
NLWKKQDLLL CHTIHESTMD EDNLPSKSVN LLDHFQKCFA ILKSNQHRGE ISSCDGPHDS
RERGKRIWKA IRVDLVFCPF EQYAFALLGW TGSRQFERDL RRYASHEKKM MIDNHALYDK
TKRVFVKCES EEEIFGHLGL EYIDPVERNA
//
