2IYI:
reference: Crystal structures of the AppA BLUF domain photoreceptor provide insights into blue light-mediated signal transduction., Jung A, Reinstein J, Domratcheva T, Shoeman RL, Schlichting I, J Mol Biol. 2006 Sep 29;362(4):717-32. Epub 2006 Jul 15. PMID: 16949615

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