FIGURE 3.

Comparison of the Glu-249–Pro-250–Thr-251 (EPT) motif in derCD23 structures. A, superimposition of the EPT motif in Ca²⁺-bound derCD23 (orange) and two conformations of Ca²⁺-free derCD23 structures (blue and cyan). In the Ca²⁺-bound and Ca²⁺-free conformation 1 derCD23 structures, Pro-250 adopts a cis-configuration. Pro-250 adopts a trans-configuration in conformation 2 of the Ca²⁺-free derCD23 structure. B, EPT motif in the Ca²⁺-bound derCD23 structure. C, EPT motif in conformation 1 of the Ca²⁺-free derCD23 structure. D, EPT motif in conformation 2 of the Ca²⁺-free derCD23 structure.