4TMA:
reference: Direct control of type IIA topoisomerase activity by a chromosomally encoded regulatory protein., Vos SM, Lyubimov AY, Hershey DM, Schoeffler AJ, Sengupta S, Nagaraja V, Berger JM, Genes Dev. 2014 Jul 1;28(13):1485-97. doi: 10.1101/gad.241984.114. PMID: 24990966

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