Figure 3.

A 15-mer polyalanine peptide is able to compete for binding to I-Ag7 with the 323–339 OVA peptide. (Left) A competition assay using different concentrations of a polyalanine peptide containing residues Glu-55, Leu-60, Asn-62, Ile-63 (●) or with a nonbinder peptide (○) 48–61 HEL. (Right) A competition assay using different concentrations of a 15-mer polyalanine peptide with an arginine at the carboxyl terminus to improve solubility (●). The results with the nonbinder peptide (○) 48–61 HEL from the left panel are included. Competitor peptides were tested as detailed in the legend of Fig. 2.