3M0B:
reference: Ru-porphyrin protein scaffolds for sensing O2., Winter MB, McLaurin EJ, Reece SY, Olea C Jr, Nocera DG, Marletta MA, J Am Chem Soc. 2010 Apr 28;132(16):5582-3. PMID: 20373741

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