3WCK:
reference: SuperNova, a monomeric photosensitizing fluorescent protein for chromophore-assisted light inactivation., Takemoto K, Matsuda T, Sakai N, Fu D, Noda M, Uchiyama S, Kotera I, Arai Y, Horiuchi M, Fukui K, Ayabe T, Inagaki F, Suzuki H, Nagai T, Sci Rep. 2013 Sep 17;3:2629. doi: 10.1038/srep02629. PMID: 24043132

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