Send to

Choose Destination
See comment in PubMed Commons below
Cell. 1999 Aug 6;98(3):397-408.

Structure of the DNA repair enzyme endonuclease IV and its DNA complex: double-nucleotide flipping at abasic sites and three-metal-ion catalysis.

Author information

Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA.


Endonuclease IV is the archetype for a conserved apurinic/apyrimidinic (AP) endonuclease family that primes DNA repair synthesis by cleaving the DNA backbone 5' of AP sites. The crystal structures of Endonuclease IV and its AP-DNA complex at 1.02 and 1.55 A resolution reveal how an alpha8beta8 TIM barrel fold can bind dsDNA. Enzyme loops intercalate side chains at the abasic site, compress the DNA backbone, bend the DNA approximately 90 degrees, and promote double-nucleotide flipping to sequester the extrahelical AP site in an enzyme pocket that excludes undamaged nucleotides. These structures suggest three Zn2+ ions directly participate in phosphodiester bond cleavage and prompt hypotheses that double-nucleotide flipping and sharp bending by AP endonucleases provide exquisite damage specificity while aiding subsequent base excision repair pathway progression.

[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons


    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center