Structural changes in the lectin domain of CD23, the low-affinity IgE receptor, upon calcium binding.
Structural changes in the lectin domain of CD23, the low-affinity IgE receptor, upon calcium binding.
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DOI：
10.1016/j.str.2006.03.017
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发表时间：
2006-06
期刊：
影响因子：
5.7
通讯作者：
B. A. Wurzburg;S. Tarchevskaya;T. Jardetzky
中科院分区：
文献类型：
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作者：
B. A. Wurzburg;S. Tarchevskaya;T. Jardetzky
CD23是低亲和力的免疫球蛋白E受体(FcɛRII)，调节免疫球蛋白E的合成，也介导免疫球蛋白E依赖的抗原转运和加工。CD23是一种独特的Fc受体，属于C型凝集素样结构域超家族，以一种不寻常的非凝集素样方式与IgE结合，需要钙而不是碳水化合物。我们已经解决了人CD23凝集素结构域在存在和不存在钙离子的情况下的高分辨晶体结构。这些晶体结构与之前确定的核磁共振结构有很大的不同，表明钙结合发生在主要结合部位，而不是在人CD23中似乎缺乏的辅助部位。载脂蛋白和钙结合结构之间的构象差异表明，IgE-Fc结合既是钙依赖的，又是碳水化合物非依赖的。
CD23, the low-affinity receptor for IgE (FcɛRII), regulates IgE synthesis and also mediates IgE-dependent antigen transport and processing. CD23 is a unique Fc receptor belonging to the C-type lectin-like domain superfamily and binds IgE in an unusual, non-lectin-like manner, requiring calcium but not carbohydrate. We have solved the high-resolution crystal structures of the human CD23 lectin domain in the presence and absence of Ca2+. The crystal structures differ significantly from a previously determined NMR structure and show that calcium binding occurs at the principal binding site, but not at an auxiliary site that appears to be absent in human CD23. Conformational differences between the apo and Ca2+bound structures suggest how IgE-Fc binding can be both calcium-dependent and carbohydrate-independent.