1TF7:
reference: Visualizing a circadian clock protein: crystal structure of KaiC and functional insights., Pattanayek R, Wang J, Mori T, Xu Y, Johnson CH, Egli M, Mol Cell 2004 Aug 13;15(3):375-88. PMID: 15304218

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