3FPV:
reference: The oligomeric assembly of the novel haem-degrading protein HbpS is essential for interaction with its cognate two-component sensor kinase., Lucana DO, Bogel G, Zou P, Groves MR, J Mol Biol. 2009 Mar 6;386(4):1108-22. PMID: 19244623

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