1b43

Publication Abstract from PubMed

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.

Structure of the DNA repair and replication endonuclease and exonuclease FEN-1: coupling DNA and PCNA binding to FEN-1 activity.,Hosfield DJ, Mol CD, Shen B, Tainer JA Cell. 1998 Oct 2;95(1):135-46. PMID:9778254^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.