5LLS:
reference: Comparative Analysis of Binding Kinetics and Thermodynamics of Dipeptidyl Peptidase-4 Inhibitors and Their Relationship to Structure., Schnapp G, Klein T, Hoevels Y, Bakker RA, Nar H, J Med Chem. 2016 Aug 25;59(16):7466-77. doi: 10.1021/acs.jmedchem.6b00475. Epub, 2016 Aug 4. PMID: 27438064

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