3EPG:
reference: Lesion bypass of N2-ethylguanine by human DNA polymerase iota., Pence MG, Blans P, Zink CN, Hollis T, Fishbein JC, Perrino FW, J Biol Chem. 2009 Jan 16;284(3):1732-40. Epub 2008 Nov 3. PMID: 18984581

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