DNA polymerase kappa; DINB protein; DINP (POLK, DINB1)

Function

• DNA polymerase specifically involved in DNA repair
• translesion synthesis
  • other high-fidelity DNA polymerases cannot proceed
  • DNA synthesis stalls
  • inserts the correct base causes frequent base transitions, transversions and frameshifts.
  • lacks 3'-5' proofreading exonuclease activity
  • forms a Schiff base with 5'-deoxyribose phosphate at abasic sites
  • does not have lyase activity
• 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

More general terms

• DNA polymerase
• zinc finger protein
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=51426
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:51426
• OMIM: https://mirror.omim.org/entry/605650
• UniProt: http://www.uniprot.org/uniprot/Q9UBT6.html