Structure and biochemical analysis of the heparin-induced E1 dimer of the amyloid precursor protein
Structure and biochemical analysis of the heparin-induced E1 dimer of the amyloid precursor protein
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DOI：
10.1073/pnas.0911326107
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发表时间：
2010-03-23
影响因子：
11.1
通讯作者：
Than, Manuel E.
中科院分区：
文献类型：
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作者：
Dahms, Sven O.;Hoefgen, Sandra;Than, Manuel E.
淀粉样前体蛋白(APP)在阿尔茨海默病的病理中起关键作用，但APP及其类似物对哺乳动物的神经元发育和细胞动态平衡也是必不可少的。我们测定了整个N-末端APP-E1结构域的晶体结构，该结构域由生长因子样结构域和铜结合结构域组成，分辨率为2.7埃，表明E1作为一个刚性功能实体发挥作用。这两个亚区通过进化上保守的界面区以依赖于pH的方式紧密地相互作用。两个E1实体与肝素相互作用时发生二聚反应，需要8-12个糖环才能形成肝素桥联的APP-E1二聚体，这是一个吸热和pH依赖的过程，其特点是微摩尔解离常数低。有限的蛋白质降解证实，在溶液中获得的肝素桥联的E1二聚体对应于我们晶体中的二聚体接触，使我们能够对该肝素-[APP-E1](2)复合体进行建模。相应地，基于APP的信号转导、细胞-细胞-和/或细胞-ECM相互作用应依赖于肝素诱导的二聚化以及pH，认为APP可以根据其(亚)细胞定位而发挥不同的功能。
The amyloid precursor protein (APP) is the key player in Alzheimer's disease pathology, yet APP and its analogues are also essential for neuronal development and cell homeostasis in mammals. We have determined the crystal structure of the entire N-terminal APP-E1 domain consisting of the growth factor like and the copper binding domains at 2.7-angstrom resolution and show that E1 functions as a rigid functional entity. The two subdomains interact tightly in a pH-dependent manner via an evolutionarily conserved interface area. Two E1 entities dimerize upon their interaction with heparin, requiring 8-12 sugar rings to form the heparin-bridged APP-E1 dimer in an endothermic and pH-dependent process that is characterized by a low micromolar dissociation constant. Limited proteolysis confirms that the heparin-bridged E1 dimers obtained in solution correspond to a dimer contact in our crystal, enabling us to model this heparin-[APP-E1](2) complex. Correspondingly, the APP-based signal transduction, cell-cell- and/or cell-ECM interaction should depend on dimerization induced by heparin, as well as on pH, arguing that APP could fulfill different functions depending on its (sub) cellular localization.