3OJJ:
reference: A hyperactive cobalt-substituted extradiol-cleaving catechol dioxygenase., Fielding AJ, Kovaleva EG, Farquhar ER, Lipscomb JD, Que L Jr, J Biol Inorg Chem. 2010 Dec 14. PMID: 21153851

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