5ugp

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DNA polymerase beta complex with a 1nt gap and dCMPPNPDNA polymerase beta complex with a 1nt gap and dCMPPNP

Structural highlights

5ugp is a 4 chain structure with sequence from Homo sapiens and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.955Å
Ligands:,
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

DNA polymerases catalyze efficient and high-fidelity DNA synthesis. While this reaction favors nucleotide incorporation, polymerases also catalyze a reverse reaction, pyrophosphorolysis, that removes the DNA primer terminus and generates deoxynucleoside triphosphates. Because pyrophosphorolysis can influence polymerase fidelity and sensitivity to chain-terminating nucleosides, we analyzed pyrophosphorolysis with human DNA polymerase beta and found the reaction to be inefficient. The lack of a thio-elemental effect indicated that this reaction was limited by a nonchemical step. Use of a pyrophosphate analog, in which the bridging oxygen is replaced with an imido group (PNP), increased the rate of the reverse reaction and displayed a large thio-elemental effect, indicating that chemistry was now rate determining. Time-lapse crystallography with PNP captured structures consistent with a chemical equilibrium favoring the reverse reaction. These results highlight the importance of the bridging atom between the beta- and gamma-phosphates of the incoming nucleotide in reaction chemistry, enzyme conformational changes, and overall reaction equilibrium.

Modulating the DNA polymerase beta reaction equilibrium to dissect the reverse reaction.,Shock DD, Freudenthal BD, Beard WA, Wilson SH Nat Chem Biol. 2017 Jul 31. doi: 10.1038/nchembio.2450. PMID:28759020[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. ↑ Shock DD, Freudenthal BD, Beard WA, Wilson SH. Modulating the DNA polymerase beta reaction equilibrium to dissect the reverse reaction. Nat Chem Biol. 2017 Jul 31. doi: 10.1038/nchembio.2450. PMID:28759020 doi:http://dx.doi.org/10.1038/nchembio.2450

5ugp, resolution 1.96Å

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