Determination of Structural Models of the Complex between the Cytoplasmic Domain of Erythrocyte Band 3 and Ankyrin-R Repeats 13-24
Determination of Structural Models of the Complex between the Cytoplasmic Domain of Erythrocyte Band 3 and Ankyrin-R Repeats 13-24
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DOI：
10.1074/jbc.m111.230326
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发表时间：
2011-06-10
影响因子：
4.8
通讯作者：
Beth, Albert H.
中科院分区：
文献类型：
--
作者：
Kim, Sunghoon;Brandon, Suzanne;Beth, Albert H.
衔接蛋白anklycer-R通过其膜结合结构域与阴离子交换蛋白（AE 1）的胞质结构域相互作用，并通过其血影蛋白结合结构域与人红细胞中血影蛋白为基础的膜骨架相互作用。这组相互作用提供了脂质双层和膜骨架之间的桥梁，从而稳定膜。AE 1的二聚胞质结构域（cdb 3）和来自锚蛋白-R的膜结合结构域（AnkD 34）的12-锚蛋白重复片段（重复13-24）的晶体结构已被报道。然而，关于这些蛋白质如何组装形成稳定复合物的结构数据尚未报道。在目前的研究中，定点自旋标记，结合电子顺磁共振（EPR）和双电子-电子共振，已被用来映射的两个蛋白质的复合物中的结合界面，并获得蛋白质间的距离约束。这些数据已被用来构建一个家庭的结构模型，与全范围的实验数据一致。这些模型表明，cdb 3外周结构域上的广泛区域主要通过疏水相互作用与AnkD 34顶部环表面上的锚蛋白重复序列18-20结合。这是先前未表征的用于cdb 3与AnkD 34结合的表面。因为已知cdb 3的第二个二聚体与锚蛋白-R的膜结合结构域的锚蛋白重复序列7-12结合，所以目前的模型对于AE 1的四聚体形式的结构性质具有重要意义，该四聚体形式被假设参与与红细胞膜中的全长锚蛋白-R的结合。
The adaptor protein ankyrin-R interacts via its membrane binding domain with the cytoplasmic domain of the anion exchange protein (AE1) and via its spectrin binding domain with the spectrin-based membrane skeleton in human erythrocytes. This set of interactions provides a bridge between the lipid bilayer and the membrane skeleton, thereby stabilizing the membrane. Crystal structures for the dimeric cytoplasmic domain of AE1 (cdb3) and for a 12-ankyrin repeat segment (repeats 13-24) from the membrane binding domain of ankyrin-R (AnkD34) have been reported. However, structural data on how these proteins assemble to form a stable complex have not been reported. In the current studies, site-directed spin labeling, in combination with electron paramagnetic resonance (EPR) and double electron-electron resonance, has been utilized to map the binding interfaces of the two proteins in the complex and to obtain inter-protein distance constraints. These data have been utilized to construct a family of structural models that are consistent with the full range of experimental data. These models indicate that an extensive area on the peripheral domain of cdb3 binds to ankyrin repeats 18-20 on the top loop surface of AnkD34 primarily through hydrophobic interactions. This is a previously uncharacterized surface for binding of cdb3 to AnkD34. Because a second dimer of cdb3 is known to bind to ankyrin repeats 7-12 of the membrane binding domain of ankyrin-R, the current models have significant implications regarding the structural nature of a tetrameric form of AE1 that is hypothesized to be involved in binding to full-length ankyrin-R in the erythrocyte membrane.