Effects of the N terminus of mouse DNA polymerase κ on the bypass of a guanine-benzo[a]pyrenyl adduct

J Biochem. 2016 Apr;159(4):471-9. doi: 10.1093/jb/mvv118. Epub 2015 Dec 3.


DNA polymerase κ (Polκ), one of the typical member of the Y-family DNA polymerases, has been demonstrated to bypass the 10S(+)-trans-anti-benzo[a]pyrene diol epoxide-N(2)-deoxyguanine adducts (BPDE-dG) efficiently and accurately. A large structural gap between the core and little finger as well as an N-clasp domain are essential to its unique translesion capability. However, whether the extreme N-terminus of Polκ is required for its activity is unclear. In this work, we constructed two mouse Polκ deletions, which have either a catalytic core (mPolκ1-516) or a core without the first 21-residues (mPolκ22-516), and tested their activities in the replication of normal and BPDE-DNA. These two Polκ deletions are nearly as efficient as the full length protein (Polκ1-852) in normal DNA synthesis. However, steady-state kinetics reveals a significant reduction in efficiency of dCTP incorporation opposite the lesion by Polκ22-516, along with increased frequencies for misinsertion compared with Polκ1-852 The next nucleotide insertion opposite the template C immediately following the BPDE-dG was also examined, and the bypass differences induced by deletions were highlighted in both insertion and extension step. We conclude that the extreme N-terminal part of Polκ is required for the processivity and fidelity of Polκ during translesion synthesis of BPDE-dG lesions.

Keywords: BPDE-dG lesions; Y-family DNA polymerase κ; enzyme fidelity; polycyclic aromatic hydrocarbons; translesion DNA synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / analogs & derivatives*
  • 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / chemistry
  • 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / metabolism
  • Animals
  • Catalytic Domain / genetics
  • DNA Adducts / metabolism*
  • DNA Damage*
  • DNA Repair*
  • DNA Replication*
  • DNA-Directed DNA Polymerase / chemistry*
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / isolation & purification
  • Deoxycytosine Nucleotides / metabolism
  • Deoxyguanosine / analogs & derivatives*
  • Deoxyguanosine / chemistry
  • Enzyme Assays
  • Kinetics
  • Mice
  • Mutagenesis


  • DNA Adducts
  • Deoxycytosine Nucleotides
  • benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide-DNA
  • 2'-deoxycytidine 5'-triphosphate
  • 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide
  • 7,8-dihydroxy-9,10-epoxide-7,8,9,10-tetrahydrobenzo(a)pyrene-10-deoxyguanosine
  • DNA-Directed DNA Polymerase
  • Polk protein, mouse
  • Deoxyguanosine