1rxm

Publication Abstract from PubMed

Flap EndoNuclease-1 (FEN-1) and the processivity factor proliferating cell nuclear antigen (PCNA) are central to DNA replication and repair. To clarify the molecular basis of FEN-1 specificity and PCNA activation, we report here structures of FEN-1:DNA and PCNA:FEN-1-peptide complexes, along with fluorescence resonance energy transfer (FRET) and mutational results. FEN-1 binds the unpaired 3' DNA end (3' flap), opens and kinks the DNA, and promotes conformational closing of a flexible helical clamp to facilitate 5' cleavage specificity. Ordering of unstructured C-terminal regions in FEN-1 and PCNA creates an intermolecular beta sheet interface that directly links adjacent PCNA and DNA binding regions of FEN-1 and suggests how PCNA stimulates FEN-1 activity. The DNA and protein conformational changes, composite complex structures, FRET, and mutational results support enzyme-PCNA alignments and a kinked DNA pivot point that appear suitable to coordinate rotary handoffs of kinked DNA intermediates among enzymes localized by the three PCNA binding sites.

Structural basis for FEN-1 substrate specificity and PCNA-mediated activation in DNA replication and repair.,Chapados BR, Hosfield DJ, Han S, Qiu J, Yelent B, Shen B, Tainer JA Cell. 2004 Jan 9;116(1):39-50. PMID:14718165^[1]

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