Figure 1.
A. Schematic representation of an HLA-DRB1 molecule based on crystallographic structure data. The shared epitope at amino acid positions 70-74 is located in the α helix. Reprinted with permission from reference 20. B. Representation of peptide bound to crystalline HLA DR1 from human cells. The structure in orange represents that electron density of bound peptide, while that in blue represents the van der Walls surface of DR1. This shows a view from above, as probably recognized by T lymphocytes through the T-cell receptor. The α helix is on top and the β domain helix is on bottom, with the peptide N terminus on the left. Reprinted with permission from reference 21.