Figure 3. Design of affinity peptides targeting HLA-E. (A) Crystal structure of the HLA-E-CD94/NKG2A complex from PDB ID: 3CDG. (B) Interaction between model peptide and the key area of HLA-E (pink area represents the key interacting area). (C) Site view of the interaction between the model peptide and HLA-E; (D) Screening of a peptide library generated using the method of random replacing non-key site amino acids for high affinity peptides for HLA-E. The top three peptides (i.e., highest affinity and stability) were designated PEPTIDE 1, 2 and 3.