4BJH:
reference: The mononuclear metal center of type-I dihydroorotase from aquifex aeolicus., Edwards BF, Fernando R, Martin PD, Grimley E, Cordes M, Vaishnav A, Brunzelle JS, Evans HG, Evans DR, BMC Biochem. 2013 Dec 9;14(1):36. PMID: 24314009

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