6IMX:
reference: Crown Ethers as Transthyretin Amyloidogenesis Inhibitors., Yokoyama T, Mizuguchi M, J Med Chem. 2019 Feb 28;62(4):2076-2082. doi: 10.1021/acs.jmedchem.8b01700. Epub , 2019 Feb 8. PMID: 30688456

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