3ZQH:
reference: An Exclusive alpha/beta Code Directs Allostery in TetR-Peptide Complexes., Sevvana M, Goetz C, Goeke D, Wimmer C, Berens C, Hillen W, Muller YA, J Mol Biol. 2011 Dec 9. PMID: 22178479

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