1Y28:
reference: A distal arginine in oxygen-sensing heme-PAS domains is essential to ligand binding, signal transduction, and structure., Dunham CM, Dioum EM, Tuckerman JR, Gonzalez G, Scott WG, Gilles-Gonzalez MA, Biochemistry 2003 Jul 1;42(25):7701-8. PMID: 12820879

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