Structure of the DNA repair and replication endonuclease and exonuclease FEN-1: coupling DNA and PCNA binding to FEN-1 activity.
Hosfield, D.J., Mol, C.D., Shen, B., Tainer, J.A.(1998) Cell 95: 135-146
- PubMed: 9778254
- DOI: https://doi.org/10.1016/s0092-8674(00)81789-4
- Primary Citation of Related Structures:
1B43 - PubMed Abstract:
Flap endonuclease (FEN-1) removes 5' overhanging flaps in DNA repair and processes the 5' ends of Okazaki fragments in lagging strand DNA synthesis. The crystal structure of Pyrococcus furiosus FEN-1, active-site metal ions, and mutational information indicate interactions for the single- and double-stranded portions of the flap DNA substrate and identify an unusual DNA-binding motif. The enzyme's active-site structure suggests that DNA binding induces FEN-1 to clamp onto the cleavage junction to form the productive complex. The conserved FEN-1 C terminus binds proliferating cell nuclear antigen (PCNA) and positions FEN-1 to act primarily as an exonuclease in DNA replication, in contrast to its endonuclease activity in DNA repair. FEN-1 mutations altering PCNA binding should reduce activity during replication, likely causing DNA repeat expansions as seen in some cancers and genetic diseases.
Organizational Affiliation:
Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.