3ZZP:
reference: Trimming down a protein structure to its bare foldons: spatial organization of the cooperative unit., Haglund E, Danielsson J, Kadhirvel S, Lindberg MO, Logan DT, Oliveberg M, J Biol Chem. 2012 Jan 20;287(4):2731-8. Epub 2011 Nov 22. PMID: 22117065

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