5L31:
reference: De Novo Design of an Allosteric Metalloprotein Assembly with Strained Disulfide Bonds., Churchfield LA, Medina-Morales A, Brodin JD, Perez A, Tezcan FA, J Am Chem Soc. 2016 Oct 12;138(40):13163-13166. Epub 2016 Sep 27. PMID: 27649076

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