5YEK:
reference: Structural insights into operator recognition by BioQ in the Mycobacterium smegmatis biotin synthesis pathway., Yan L, Tang Q, Guan Z, Pei K, Zou T, He J, Biochim Biophys Acta Gen Subj. 2018 Sep;1862(9):1843-1851. doi:, 10.1016/j.bbagen.2018.05.015. Epub 2018 May 28. PMID: 29852200

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