3QTK:
reference: Total Chemical Synthesis of Biologically Active Vascular Endothelial Growth Factor., Mandal K, Kent SB, Angew Chem Int Ed Engl. 2011 Jul 8. doi: 10.1002/anie.201103237. PMID: 21744452

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