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DNA polymerase kappa; DINB protein; DINP (POLK, DINB1)
Function:
1) DNA polymerase specifically involved in DNA repair
2) translesion synthesis
a) other high-fidelity DNA polymerases cannot proceed
b) DNA synthesis stalls
c) inserts the correct base causes frequent base transitions, transversions and frameshifts.
d) lacks 3'-5' proofreading exonuclease activity
e) forms a Schiff base with 5'-deoxyribose phosphate at abasic sites
f) does not have lyase activity
3) binds REV1L, PCNA
Kinetic parameters:
- Optimum pH is 6.5-7.5;
- Optimum temperature is 37 degrees Celsius
Structure:
- the catalytic core consists of fingers, palm & thumb subdomains, but the fingers & thumb subdomains are much smaller than in high-fidelity polymerases
- residues from five sequence motifs of the Y-family cluster around an active site cleft that can accommodate DNA & nucleotide substrates with relaxed geometric constraints, with consequently higher rates of misincorporation & low processivity
- belongs to the DNA polymerase type-Y family
- contains 2 UBZ-type Zn+2 fingers
- contains 1 umuC domain
Compartment: nucleus, replication foci
Alternative splicing: named isoforms=4
Expression:
- expressed at low levels in testis, spleen, prostate, ovary > kidney, colon, brain, heart, liver, lung, placenta, pancreas, peripheral blood leukocytes
Notes:
- the catalytic core allows higher rates of misincorporation than high-fidelity polymerases & relatively low processivity
General
DNA polymerase
phosphoprotein
zinc finger protein
Properties
SIZE: entity length = 870 aa
MW = 99 kD
COMPARTMENT: cell nucleus
MOTIF: UmuC {103-358}
MOTIF: Mg+2-binding site
SITE: 107-107
Mg+2-binding site
SITE: 198-198
Mg+2-binding site
SITE: 199-199
Thr phosphorylation site {T372}
Zinc finger
NAME: Zinc finger
SITE: 621-647
EFFECTOR-BOUND: Zn+2
Zinc finger
NAME: Zinc finger
SITE: 776-802
EFFECTOR-BOUND: Zn+2
Database Correlations
OMIM 605650
UniProt Q9UBT6
PFAM correlations
Entrez Gene 51426
Kegg hsa:51426
References
- UniProt :accession Q9UBT6
- NIEHS-SNPs
http://egp.gs.washington.edu/data/polk/