4UQ2:
reference: Bioorthogonal cleavage and exchange of major histocompatibility complex ligands by employing azobenzene-containing peptides., Choo JA, Thong SY, Yap J, van Esch WJ, Raida M, Meijers R, Lescar J, Verhelst SH, Grotenbreg GM, Angew Chem Int Ed Engl. 2014 Dec 1;53(49):13390-4. doi: 10.1002/anie.201406295., Epub 2014 Oct 27. PMID: 25348595

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