1b43

OverviewOverview

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.

About this StructureAbout this Structure

1B43 is a Single protein structure of sequence from Pyrococcus furiosus. Full crystallographic information is available from OCA.

ReferenceReference

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

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