Figure 4.

Crystal structure of the calnexin luminal domain and its characteristics. (A) Crystal structure of the calnexin intraluminal domain. The globular N-globular domain is shown in green while the P-domain is depicted in yellow. (B) Calnexin putative Ca²⁺-binding site, showing a Ca²⁺ ion (yellow circle) coordinated by Asp⁴¹⁶, Asp⁹⁷, Ser⁵⁴ and potentially Lys⁹⁸. (C) Calnexin carbohydrate binding site, showing the sidechains of Tyr¹⁴⁴, Lys¹⁴⁶, Tyr¹⁶⁵, Glu¹⁹⁶, Glu⁴⁰⁵ and Met¹⁶⁸ involved in the binding of carbohydrate moieties.