The complex of human AP Endonuclease-1 (APE1) with abasic DNA

The APE1 complex with abasic DNA illustrating the double-loop penetration of both the DNA major and minor grooves, and the electrostatically-positive charge and surface complementarity of APE1 for the kinked DNA helix and flipped-out abasic nucleotide. Adapted from Mol et al. Nature volume 403, 27 January 2000.