| Structural highlights
Function
POLK_HUMAN DNA polymerase specifically involved in DNA repair. Plays an important role in translesion synthesis, where the normal high-fidelity DNA polymerases cannot proceed and DNA synthesis stalls. Depending on the context, it inserts the correct base, but causes frequent base transitions, transversions and frameshifts. Lacks 3'-5' proofreading exonuclease activity. Forms a Schiff base with 5'-deoxyribose phosphate at abasic sites, but does not have lyase activity.[1] [2] [3] [4] [5] [6] [7]
Publication Abstract from PubMed
Benzo[a]pyrene (BP) is a well-known and frequently encountered carcinogen which generates a bulky DNA adduct (+)-trans-10S-BP-N2-dG (BP-dG) in cells. DNA polymerase kappa (polkappa) is the only known Y-family polymerase that bypasses BP-dG accurately and thus protects cells from genotoxic BP. Here, we report the structures of human polkappa in complex with DNA containing either a normal guanine (G) base or a BP-dG adduct at the active site and a correct deoxycytidine. The structures and supporting biochemical data reveal a unique mechanism for accurate replication by translesion synthesis past the major bulky adduct. The active site of polkappa opens at the minor groove side of the DNA substrate to accommodate the bulky BP-dG that is attached there. More importantly, polkappa stabilizes the lesion DNA substrate in the same active conformation as for regular B-form DNA substrates and the bulky BPDE ring in a 5' end pointing conformation. The BP-dG adducted DNA substrate maintains a Watson-Crick (BP-dG:dC) base pair within the active site, governing correct nucleotide insertion opposite the bulky adduct. In addition, polkappa's unique N-clasp domain supports the open conformation of the enzyme and the extended conformation of the single-stranded template to allow bypass of the bulky lesion. This work illustrates the first molecular mechanism for how a bulky major adduct is replicated accurately without strand misalignment and mis-insertion.
Structure and mechanism of error-free replication past the major benzo[a]pyrene adduct by human DNA polymerase kappa.,Jha V, Bian C, Xing G, Ling H Nucleic Acids Res. 2016 Mar 31. pii: gkw204. PMID:27034468[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Ogi T, Kato T Jr, Kato T, Ohmori H. Mutation enhancement by DINB1, a mammalian homologue of the Escherichia coli mutagenesis protein dinB. Genes Cells. 1999 Nov;4(11):607-18. PMID:10620008
- ↑ Gerlach VL, Feaver WJ, Fischhaber PL, Friedberg EC. Purification and characterization of pol kappa, a DNA polymerase encoded by the human DINB1 gene. J Biol Chem. 2001 Jan 5;276(1):92-8. PMID:11024016 doi:http://dx.doi.org/10.1074/jbc.M004413200
- ↑ Fischhaber PL, Gerlach VL, Feaver WJ, Hatahet Z, Wallace SS, Friedberg EC. Human DNA polymerase kappa bypasses and extends beyond thymine glycols during translesion synthesis in vitro, preferentially incorporating correct nucleotides. J Biol Chem. 2002 Oct 4;277(40):37604-11. Epub 2002 Jul 26. PMID:12145297 doi:10.1074/jbc.M206027200
- ↑ Haracska L, Prakash L, Prakash S. Role of human DNA polymerase kappa as an extender in translesion synthesis. Proc Natl Acad Sci U S A. 2002 Dec 10;99(25):16000-5. Epub 2002 Nov 20. PMID:12444249 doi:10.1073/pnas.252524999
- ↑ Wolfle WT, Washington MT, Prakash L, Prakash S. Human DNA polymerase kappa uses template-primer misalignment as a novel means for extending mispaired termini and for generating single-base deletions. Genes Dev. 2003 Sep 1;17(17):2191-9. PMID:12952891 doi:http://dx.doi.org/10.1101/gad.1108603
- ↑ Haracska L, Prakash L, Prakash S. A mechanism for the exclusion of low-fidelity human Y-family DNA polymerases from base excision repair. Genes Dev. 2003 Nov 15;17(22):2777-85. PMID:14630940 doi:10.1101/gad.1146103
- ↑ Yasui M, Suzuki N, Miller H, Matsuda T, Matsui S, Shibutani S. Translesion synthesis past 2'-deoxyxanthosine, a nitric oxide-derived DNA adduct, by mammalian DNA polymerases. J Mol Biol. 2004 Nov 26;344(3):665-74. PMID:15533436 doi:S0022-2836(04)01222-7
- ↑ Jha V, Bian C, Xing G, Ling H. Structure and mechanism of error-free replication past the major benzo[a]pyrene adduct by human DNA polymerase kappa. Nucleic Acids Res. 2016 Mar 31. pii: gkw204. PMID:27034468 doi:http://dx.doi.org/10.1093/nar/gkw204
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