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terminal deoxynucleotidyltransferase (terminal addition enzyme, terminal deoxynucleotidyltransferase, terminal transferase, DNTT, TDT)
Function:
- template-independent DNA polymerase which catalyzes the random addition of deoxynucleoside 5'-triphosphate to the 3'-end of a DNA initiator
- one of the in vivo functions of this enzyme is the addition of nucleotides at the junction (N region) of rearranged Ig heavy chain & T-cell receptor gene segments during maturation of B-cells & T-cells
- interacts with PRP19 & DNTTIP1
- forms a ternary complex with DNTTIP2 & core histone, released from DNTTIP2/core histone complex by PCNA
deoxynucleoside triphosphate + DNA(n) diphosphate + DNA(n+1)
Cofactor: Mg+2
Structure:
- belongs to the DNA polymerase type-X family
- contains 1 BRCT domain
Compartment: nucleus
Pathology:
- very high levels of enzyme activity have been detected in certain acute leukemic cells
General
DNA nucleotidylexotransferase
Properties
SIZE: entity length = 509 aa
MW = 58 kD
COMPARTMENT: cell nucleus
MOTIF: BRCA1 C-terminal (BRCT) motif
SITE: 27-124
Mediates interaction with DNTTIP2 {151-509}
MOTIF: DNA-binding motif
SITE: 336-345
Mg+2-binding site
SITE: 343-343
Mg+2-binding site
SITE: 345-345
Mg+2-binding site
SITE: 433-433
Database Correlations
OMIM 187410
UniProt P04053
PFAM correlations
Kegg hsa:1791
ENZYME 2.7.7.31
References
- UniProt :accession P04053
- Tietz Fundamentals of Clinical Chemistry 3rd ed, WB
Saunders, 1987 pg 413