4LJD:
reference: Structural Evidence for a Two-Regime Photobleaching Mechanism in a Reversibly Switchable Fluorescent Protein., Duan C, Adam V, Byrdin M, Ridard J, Kieffer-Jaquinod S, Morlot C, Arcizet D, Demachy I, Bourgeois D, J Am Chem Soc. 2013 Oct 7. PMID: 24059326

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