4SKN:
reference: A nucleotide-flipping mechanism from the structure of human uracil-DNA glycosylase bound to DNA., Slupphaug G, Mol CD, Kavli B, Arvai AS, Krokan HE, Tainer JA, Nature 1996 Nov 7;384(6604):87-92. PMID: 8900285

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).