Differential Specificity of Human and Escherichia coli Endonuclease III and VIII Homologues for Oxidative Base Lesions
| Autor: | Atsushi Katafuchi, Toshiaki Nakano, Hiroshi Ide, Fumio Hanaoka, Aya Masaoka, Shigenori Iwai, Hiroaki Terato |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
DNA Repair
Pyrimidine NEIL1 Oxidative phosphorylation medicine.disease_cause Biochemistry DNA Glycosylases Substrate Specificity HeLa Deoxyribonuclease (Pyrimidine Dimer) chemistry.chemical_compound DNA-(Apurinic or Apyrimidinic Site) Lyase Escherichia coli medicine Humans AP site Molecular Biology biology Oligonucleotide Chemistry Escherichia coli Proteins Active site Purine Nucleosides Cell Biology biology.organism_classification Enzyme Activation Kinetics Cross-Linking Reagents biology.protein Oxidation-Reduction HeLa Cells |
| Zdroj: | Journal of Biological Chemistry. 279:14464-14471 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m400393200 |
| Popis: | In human cells, oxidative pyrimidine lesions are restored by the base excision repair pathway initiated by homologues of Endo III (hNTH1) and Endo VIII (hNEIL1 and hNEIL2). In this study we have quantitatively analyzed and compared their activity toward nine oxidative base lesions and an apurinic/apyrimidinic (AP) site using defined oligonucleotide substrates. hNTH1 and hNEIL1 but not hNEIL2 excised the two stereoisomers of thymine glycol (5R-Tg and 5S-Tg), but their isomer specificity was markedly different: the relative activity for 5R-Tg:5S-Tg was 13:1 for hNTH1 and 1.5:1 for hNEIL1. This was also the case for their Escherichia coli homologues: the relative activity for 5R-Tg:5S-Tg was 1:2.5 for Endo III and 3.2:1 for Endo VIII. Among other tested lesions for hNTH1, an AP site was a significantly better substrate than urea, 5-hydroxyuracil (hoU), and guanine-derived formamidopyrimidine (mFapyG), whereas for hNEIL1 these base lesions and an AP site were comparable substrates. In contrast, hNEIL2 recognized an AP site exclusively, and the activity for hoU and mFapyG was marginal. hNEIL1, hNEIL2, and Endo VIII but not hNTH1 and Endo III formed cross-links to oxanine, suggesting conservation of the -fold of the active site of the Endo VIII homologues. The profiles of the excision of the Tg isomers with HeLa and E. coli cell extracts closely resembled those of hNTH1 and Endo III, confirming their major contribution to the repair of Tg isomers in cells. However, detailed analysis of the cellular activity suggests that hNEIL1 has a significant role in the repair of 5S-Tg in human cells. |
| Databáze: | OpenAIRE |
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