4NCW:
reference: Versatile C(3)-symmetric scaffolds and their use for covalent stabilization of the foldon trimer., Berthelmann A, Lach J, Grawert MA, Groll M, Eichler J, Org Biomol Chem. 2014 Apr 28;12(16):2606-14. doi: 10.1039/c3ob42251h. PMID: 24637609

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