Issues

Crystal structure of the multiple sclerosis–associated HLA-DR2 molecule with a bound peptide from human myelin basic protein (MBP). An aromatic residue of the MBP peptide, phenylalanine (right), is bound in a large and primarily hydrophobic pocket of HLA-DR2. This pocket distinguishes DR2 from DR molecules associated with other autoimmune diseases. Neighboring MBP peptide residues, histidine and phenylalanine (left), as well as lysine (top, center), are solvent exposed and represent important TCR contact residues of the peptide. See related article in this issue by Smith et al., pp. 1511–1520.