3ZXS:
reference: CryB from Rhodobacter sphaeroides: a unique class of cryptochromes with new cofactors., Geisselbrecht Y, Fruhwirth S, Schroeder C, Pierik AJ, Klug G, Essen LO, EMBO Rep. 2012 Jan 31. doi: 10.1038/embor.2012.2. PMID: 22290493

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