1NML:
reference: Structural basis for the mechanism of Ca(2+) activation of the di-heme cytochrome c peroxidase from Pseudomonas nautica 617., Dias JM, Alves T, Bonifacio C, Pereira AS, Trincao J, Bourgeois D, Moura I, Romao MJ, Structure (Camb) 2004 Jun;12(6):961-73. PMID: 15274917

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