3UE6:
reference: Crystal structures of Aureochrome1 LOV suggest new design strategies for optogenetics., Mitra D, Yang X, Moffat K, Structure. 2012 Apr 4;20(4):698-706. doi: 10.1016/j.str.2012.02.016. Epub 2012, Apr 3. PMID: 22483116

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