1QQD:
reference: Structure of human histocompatibility leukocyte antigen (HLA)-Cw4, a ligand for the KIR2D natural killer cell inhibitory receptor., Fan QR, Wiley DC, J Exp Med 1999 Jul 5;190(1):113-23. PMID: 10429675

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