INFLUENCE OF APOLIPOPROTEIN E STRUCTURE ON FUNCTION

项目1：载脂蛋白E结构对功能的影响： 载脂蛋白（apo-）E是脂蛋白代谢的主要介质， 它与低密度脂蛋白（LDL）受体成员的相互作用 家人apo-E结构的多态性差异对 对apo-E介导的脂蛋白代谢的影响。此外，apo-E4，a 结构异构体是阿尔茨海默病的主要危险因素， 其他神经退行性疾病。因此， 了解apo-E结构对其功能的影响。的 本提案的总体目标侧重于结构/职能 apo-E与脂蛋白代谢的关系，使用x射线 晶体学作为主要的结构工具。此前，我们介绍了 结构域相互作用的概念，即apo-E的两个结构域 影响彼此的功能属性-并确定这是如何 相互作用指导apo-E4对极低密度的结合偏好 脂蛋白在这个建议中，我们将扩展我们的研究领域， 相互作用，以阐明载脂蛋白- E4，探索结构域相互作用的其他方面，无论是在体外还是在体外， 体内模型系统，并获得更好的理解的结构， 脂质结合的apo-E。此外，我们将确定LDL的结构 受体，并定义LDL受体的结构，并定义 受体和结合的apo-E的分子界面。我们提出了两 具体目标是实现这些目标。在目标1中，我们将确定 LDL受体的X射线结构和几种生理学相关的 apo-E的形式。除了无脂质形式外，脂质的结构- 将测定相关或洗涤剂处理的apo-E，以确定 当apo-E从一个无脂质的受体- 非活性状态转变为与脂质相关的受体活性状态。在目标2中， 将研究结构域相互作用对受体结合功能的影响 并检验第二组不同的精氨酸残基 在apo-E的铰链区内的氨基酸序列有助于受体结合活性。 拟议的研究将导致新的见解如何结构 载脂蛋白E的差异有助于脂蛋白异构体特异性作用 代谢、心脏病和阿尔茨海默病。

Project 1: Influence of Apolipoprotein E Structure on Function: Apolipoprotein (apo-)E is a major mediator of lipoprotein metabolism via its interaction with members of the low density lipoprotein (LDL) receptor family. Polymorphic differences in the structure of apo-E have a major impact on apo-E-mediated lipoprotein metabolism. In addition, apo-E4, a structural isoform, is a major risk factor for Alzheimer's disease and other neurodegenerative disorders. Therefore, it is critically important to understand the influence of apo-E structure on its functions. The overall objective of this proposal focuses on the structure/function relationships of apo-E-related to lipoprotein metabolism, using x-ray crystallography as the primary structural tool. Previously, we introduced the concept of domain interaction-that the two structural domains of apo-E influence each other's functional properties-and determined how this interaction directs apo-E4's binding preference for very low density lipoproteins. In this proposal, we will extend our studies on domain interaction to elucidate the increased receptor-binding activity of apo- E4, to explore other aspects of domain interaction in both in vitro and in vivo model systems, and to gain a better understanding of the structure of lipid-bound apo-E. In addition, we will determine the structure of the LDL receptor and define the structure of the LDL receptor and define the molecular interface of the receptor and bound apo-E. We propose two specific aims to achieve these objectives. In Aim 1, we will determine the x-ray structures of the LDL receptor and several physiologically relevant forms of apo-E. In addition to lipid-free forms, the structures of lipid- associated or detergent-treated apo-E will be determined to define the structural change that occurs when apo-E goes from a lipid-free, receptor- inactive state to a lipid-associated, receptor-active state. In Aim 2, we will study the effect of domain interaction on receptor-binding function and test the hypothesis that a second distinct group of arginine residues within the hinge region of apo-E contributes to receptor-binding activity. The proposed studies will lead to new insights into how the structural differences in apo-E contribute to isoform-specific effects in lipoprotein metabolism, heart disease, and Alzheimer's disease.