1B1B:
reference: Crystal structure of the iron-dependent regulator (IdeR) from Mycobacterium tuberculosis shows both metal binding sites fully occupied., Pohl E, Holmes RK, Hol WG, J Mol Biol 1999 Jan 22;285(3):1145-56. PMID: 9887269

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