Structure of human DNA polymerase beta complexed with 8-ClG in the template base paired with incoming non-hydrolyzable GTPStructure of human DNA polymerase beta complexed with 8-ClG in the template base paired with incoming non-hydrolyzable GTP

Structural highlights

6crh is a 4 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:, ,
NonStd Res:
Gene:POLB (HUMAN)
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[DPOLB_HUMAN] Repair polymerase that plays a key role in base-excision repair. Has 5'-deoxyribose-5-phosphate lyase (dRP lyase) activity that removes the 5' sugar phosphate and also acts as a DNA polymerase that adds one nucleotide to the 3' end of the arising single-nucleotide gap. Conducts 'gap-filling' DNA synthesis in a stepwise distributive fashion rather than in a processive fashion as for other DNA polymerases.[1] [2] [3] [4]

Publication Abstract from PubMed

Chronic inflammation is closely associated with cancer development. One possible mechanism for inflammation-induced carcinogenesis is DNA damage caused by reactive halogen species, such as hypochlorous acid, which is released by myeloperoxidase to kill pathogens. Hypochlorous acid can attack genomic DNA to produce 8-chloro-2'-deoxyguanosine (ClG) as a major lesion. It has been postulated that ClG promotes mutagenic replication using its syn conformer; yet, the structural basis for ClG-induced mutagenesis is unknown. We obtained crystal structures and kinetics data for nucleotide incorporation past a templating ClG using human DNA polymerase beta (polbeta) as a model enzyme for high-fidelity DNA polymerases. The structures showed that ClG formed base pairs with incoming dCTP and dGTP using its anti and syn conformers, respectively. Kinetic studies showed that polbeta incorporated dGTP only 15-fold less efficiently than dCTP, suggesting that replication across ClG is promutagenic. Two hydrogen bonds between syn-ClG and anti-dGTP and a water-mediated hydrogen bond appeared to facilitate mutagenic replication opposite the major halogenated guanine lesion. These results suggest that ClG in DNA promotes G to C transversion mutations by forming Hoogsteen base pairing between syn-ClG and anti-G during DNA synthesis.

Promutagenicity of 8-Chloroguanine, A Major Inflammation-Induced Halogenated DNA Lesion.,Kou Y, Koag MC, Lee S Molecules. 2019 Sep 27;24(19). pii: molecules24193507. doi:, 10.3390/molecules24193507. PMID:31569643[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Bennett RA, Wilson DM 3rd, Wong D, Demple B. Interaction of human apurinic endonuclease and DNA polymerase beta in the base excision repair pathway. Proc Natl Acad Sci U S A. 1997 Jul 8;94(14):7166-9. PMID:9207062
  2. Matsumoto Y, Kim K, Katz DS, Feng JA. Catalytic center of DNA polymerase beta for excision of deoxyribose phosphate groups. Biochemistry. 1998 May 5;37(18):6456-64. PMID:9572863 doi:10.1021/bi9727545
  3. DeMott MS, Beyret E, Wong D, Bales BC, Hwang JT, Greenberg MM, Demple B. Covalent trapping of human DNA polymerase beta by the oxidative DNA lesion 2-deoxyribonolactone. J Biol Chem. 2002 Mar 8;277(10):7637-40. Epub 2002 Jan 22. PMID:11805079 doi:10.1074/jbc.C100577200
  4. Parsons JL, Dianova II, Khoronenkova SV, Edelmann MJ, Kessler BM, Dianov GL. USP47 is a deubiquitylating enzyme that regulates base excision repair by controlling steady-state levels of DNA polymerase beta. Mol Cell. 2011 Mar 4;41(5):609-15. doi: 10.1016/j.molcel.2011.02.016. PMID:21362556 doi:10.1016/j.molcel.2011.02.016
  5. Kou Y, Koag MC, Lee S. Promutagenicity of 8-Chloroguanine, A Major Inflammation-Induced Halogenated DNA Lesion. Molecules. 2019 Sep 27;24(19). pii: molecules24193507. doi:, 10.3390/molecules24193507. PMID:31569643 doi:http://dx.doi.org/10.3390/molecules24193507

6crh, resolution 2.33Å

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