WRN exonuclease structure and molecular mechanism imply an editing role in DNA end processing
- 23 April 2006
- journal article
- research article
- Published by Springer Nature in Nature Structural & Molecular Biology
- Vol. 13 (5) , 414-422
- https://doi.org/10.1038/nsmb1088
Abstract
WRN is unique among the five human RecQ DNA helicases in having a functional exonuclease domain (WRN-exo) and being defective in the premature aging and cancer-related disorder Werner syndrome. Here, we characterize WRN-exo crystal structures, biochemical activity and participation in DNA end joining. Metal-ion complex structures, active site mutations and activity assays reveal a nuclease mechanism mediated by two metal ions. The DNA end–binding Ku70/80 complex specifically stimulates WRN-exo activity, and structure-based mutational inactivation of WRN-exo alters DNA end joining in human cells. We furthermore establish structural and biochemical similarities of WRN-exo to DnaQ-family replicative proofreading exonucleases, describing WRN-specific adaptations consistent with double-stranded DNA specificity and functionally important conformational changes. These results indicate WRN-exo is a human DnaQ family member and support DnaQ-like proofreading activities stimulated by Ku70/80, with implications for WRN functions in age-related pathologies and maintenance of genomic integrity.Keywords
This publication has 50 references indexed in Scilit:
- Elevated telomere-telomere recombination in WRN-deficient, telomere dysfunctional cells promotes escape from senescence and engagement of the ALT pathwayGenes & Development, 2005
- Structure and function of the double-strand break repair machineryDNA Repair, 2004
- The Werner syndrome protein at the crossroads of DNA repair and apoptosisMechanisms of Ageing and Development, 2004
- Linkage between Werner Syndrome Protein and the Mre11 Complex via Nbs1Journal of Biological Chemistry, 2004
- Werner Syndrome Protein--Unwinding Function to Explain DiseaseScience of Aging Knowledge Environment, 2004
- Werner syndrome and the function of the Werner protein; what they can teach us about the molecular aging process.Carcinogenesis: Integrative Cancer Research, 2003
- A Minimal Exonuclease Domain of WRN Forms a Hexamer on DNA and Possesses both 3‘−5‘ Exonuclease and 5‘-Protruding Strand Endonuclease ActivitiesBiochemistry, 2002
- Human glutathione transferase A4-4 crystal structures and mutagenesis reveal the basis of high catalytic efficiency with toxic lipid peroxidation productsJournal of Molecular Biology, 1999
- Structural principles for the inhibition of the 3′-5′ exonuclease activity of Escherichia coli DNA polymerase I by phosphorothioatesJournal of Molecular Biology, 1998
- Crystal Structures of an NH2-Terminal Fragment of T4 DNA Polymerase and Its Complexes with Single-Stranded DNA and with Divalent Metal IonsBiochemistry, 1996