3PCY:
reference: The crystal structure of mercury-substituted poplar plastocyanin at 1.9-A resolution., Church WB, Guss JM, Potter JJ, Freeman HC, J Biol Chem 1986 Jan 5;261(1):234-7. PMID: 3941073

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