PCNA and XPF cooperate to distort DNA substrates

Richard David Hutton, Timothy David Craggs, Malcolm F White, Carlos Penedo

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18 Citations (Scopus)
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XPF is a structure-specific endonuclease that preferentially cleaves 3' DNA flaps during a variety of repair processes. The crystal structure of a crenarchaeal XPF protein bound to a DNA duplex yielded insights into how XPF might recognise branched DNA structures, and recent kinetic data have demonstrated that the sliding clamp PCNA acts as an essential cofactor, possibly by allowing XPF to distort the DNA structure into a proper conformation for efficient cleavage to occur. Here, we investigate the solution structure of the 3'-flap substrate bound to XPF in the presence and absence of PCNA using intramolecular Forster resonance energy transfer (FRET). We demonstrate that recognition of the flap substrate by XPF involves major conformational changes of the DNA, including a 90 degrees kink of the DNA duplex and organization of the single-stranded flap. In the presence of PCNA, there is a further substantial reorganization of the flap substrate bound to XPF, providing a structural basis for the observation that PCNA has an essential catalytic role in this system. The wider implications of these observations for the plethora of PCNA-dependent enzymes are discussed.

Original languageEnglish
Pages (from-to)1664-1675
Number of pages12
JournalNucleic Acids Research
Issue number5
Early online date11 Dec 2009
Publication statusPublished - Mar 2010


  • Single-stranded-DNA
  • Heterotrimeric PCNA
  • Crystal-structure
  • Sulfolobus-solfataricus
  • Flap endonuclease-1
  • Structural basis
  • Energy-transfer
  • Complex
  • Binding
  • Repair


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