1XQO:
reference: A DNA glycosylase from Pyrobaculum aerophilum with an 8-oxoguanine binding mode and a noncanonical helix-hairpin-helix structure., Lingaraju GM, Sartori AA, Kostrewa D, Prota AE, Jiricny J, Winkler FK, Structure. 2005 Jan;13(1):87-98. PMID: 15642264

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