3TUV:
reference: Anion Activation Site of Insulin-degrading Enzyme., Noinaj N, Song ES, Bhasin S, Alper BJ, Schmidt WK, Hersh LB, Rodgers DW, J Biol Chem. 2012 Jan 2;287(1):48-57. Epub 2011 Nov 2. PMID: 22049080

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