1UWN:
reference: Initial events in the photocycle of photoactive yellow protein., Kort R, Hellingwerf KJ, Ravelli RB, J Biol Chem. 2004 Jun 18;279(25):26417-24. Epub 2004 Mar 16. PMID: 15026418

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