1WWJ:
reference: Tetrameric architecture of the circadian clock protein KaiB. A novel interface for intermolecular interactions and its impact on the circadian rhythm., Hitomi K, Oyama T, Han S, Arvai AS, Getzoff ED, J Biol Chem 2005 May 13;280(19):19127-35. Epub 2005 Feb 16. PMID: 15716274

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