5ICU:
reference: The CopC Family: Structural and Bioinformatic Insights into a Diverse Group of Periplasmic Copper Binding Proteins., Lawton TJ, Kenney GE, Hurley JD, Rosenzweig AC, Biochemistry. 2016 Apr 19;55(15):2278-90. doi: 10.1021/acs.biochem.6b00175. Epub , 2016 Apr 6. PMID: 27010565

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