1AQD:
reference: The class II MHC protein HLA-DR1 in complex with an endogenous peptide: implications for the structural basis of the specificity of peptide binding., Murthy VL, Stern LJ, Structure 1997 Oct 15;5(10):1385-96. PMID: 9351812

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