FIGURE 2.

Binding interface of IL-21Rα depicted on IL-21. IL-21 residues mutated to aspartic acid or residues containing opposite charge are labeled on the structure and color-coded according to effect on IL-21Rα and γC binding affinity. Residues shown in red and green have ≥2-fold impaired binding affinity toward either IL-21Rα or γC, respectively, whereas residues having ≥2-fold impaired IL-21Rα and γC binding affinities are shown in yellow (See Tables 1 and 2).