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Structure of human apurinic/apyrimidinic endonuclease 1 with the essential Mg2+ cofactor

Journal Article · · Acta Crystallographica. Section D: Biological Crystallography
 [1];  [2];  [3];  [3]
  1. Univ. of Maryland Baltimore County (UMBC), Baltimore, MD (United States). School of Medicine. Dept. of Biochemistry and Molecular Biology; DOE/OSTI
  2. Univ. of Maryland Baltimore County (UMBC), Baltimore, MD (United States). School of Medicine. Pharmaceutical Sciences
  3. Univ. of Maryland Baltimore County (UMBC), Baltimore, MD (United States). School of Medicine. Dept. of Biochemistry and Molecular Biology
Apurinic/apyrimidinic endonuclease 1 (APE1) mediates the repair of abasic sites and other DNA lesions and is essential for base-excision repair and strand-break repair pathways. APE1 hydrolyzes the phosphodiester bond at abasic sites, producing 5'-deoxyribose phosphate and the 3'-OH primer needed for repair synthesis. It also has additional repair activities, including the removal of 3'-blocking groups. APE1 is a powerful enzyme that absolutely requires Mg2+, but the stoichiometry and catalytic function of the divalent cation remain unresolved for APE1 and for other enzymes in the DNase I superfamily. Previously reported structures of DNA-free APE1 contained either Sm3+ or Pb2+ in the active site. However, these are poor surrogates for Mg2+ because Sm3+is not a cofactor and Pb2+ inhibits APE1, and their coordination geometry is expected to differ from that of Mg2+. A crystal structure of human APE1 was solved at 1.92 Å resolution with a single Mg2+ ion in the active site. The structure reveals ideal octahedral coordination of Mg2+ via two carboxylate groups and four water molecules. One residue that coordinates Mg2+ directly and two that bind inner-sphere water molecules are strictly conserved in the DNase I superfamily. This structure, together with a recent structure of the enzyme–product complex, inform on the stoichiometry and the role of Mg2+ in APE1-catalyzed reactions.
Research Organization:
Univ. of Maryland, College Park, MD (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER). Biological Systems Science Division
OSTI ID:
1625685
Journal Information:
Acta Crystallographica. Section D: Biological Crystallography, Journal Name: Acta Crystallographica. Section D: Biological Crystallography Journal Issue: 12 Vol. 69; ISSN ABCRE6; ISSN 0907-4449
Publisher:
International Union of CrystallographyCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (10)

Incorporation of omics analyses into artificial gravity research for space exploration countermeasure development journal January 2016
Structural comparison of AP endonucleases from the exonuclease III family reveals new amino acid residues in human AP endonuclease 1 that are involved in incision of damaged DNA journal September 2016
High-Resolution Crystal Structures Reveal Plasticity in the Metal Binding Site of Apurinic/Apyrimidinic Endonuclease I journal October 2014
Capturing snapshots of APE1 processing DNA damage journal October 2015
Substrate specificity of human apurinic/apyrimidinic endonuclease APE1 in the nucleotide incision repair pathway journal October 2018
Cloning and Characterization of a Wheat Homologue of Apurinic/Apyrimidinic Endonuclease Ape1L journal March 2014
Insights into Mechanisms of Damage Recognition and Catalysis by APE1-like Enzymes journal April 2022
Kinetic Features of 3′-5′ Exonuclease Activity of Human AP-Endonuclease APE1 journal August 2018
Effects of mono- and divalent metal ions on DNA binding and catalysis of human apurinic/apyrimidinic endonuclease 1 journal January 2016
Structure-based virtual screening toward the discovery of novel inhibitors of the DNA repair activity of the human apurinic/apyrimidinic endonuclease 1 journal September 2016

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