Fig. 3.

Observed sequence specificity in the proteolytic processing of HLA-DR peptides. Both the N-terminal and C-terminal cleavage specificity observed in HLA-DR ligand processing are shown. The sequence logo's depict six amino acids represented as P6…P1 and six amino acids as P1′…P6′, which are located at the N- (left) and C-terminal (right) scissile sites of HLA-DR-associated peptides, respectively. The residues that are statistically over-represented are shown on the upper part of the IceLogo, whereas under-represented at the lower part (95% confidence level).