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，通过 它与低密度脂蛋白受体成员的相互作用 一家人。载脂蛋白E结构的多态差异有一个主要的 对载脂蛋白E介导脂蛋白代谢的影响。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，这一点至关重要。 了解载脂蛋白E的结构对其功能的影响。这个 本提案的总体目标侧重于结构/功能 X线检测载脂蛋白E与脂蛋白代谢的关系 结晶学作为主要的结构工具。之前，我们介绍了 结构域相互作用的概念--载脂蛋白E的两个结构域 影响彼此的功能属性-并决定了这是如何 相互作用指导载脂蛋白E4‘S对极低密度的结合偏好 脂蛋白。在这个提案中，我们将扩展我们对领域的研究 相互作用以阐明apo-2受体结合活性的增强 E4，以探索体外和体内结构域相互作用的其他方面 活体模型系统，并更好地了解 脂结合载脂蛋白E此外，我们还将确定低密度脂蛋白的结构 受体和定义低密度脂蛋白受体的结构，并定义 受体与载脂蛋白E结合的分子界面我们建议两个 实现这些目标的具体目标。在目标1中，我们将确定 低密度脂蛋白受体的X射线结构及其几种生理意义 载脂蛋白E的形式。除了无脂形式外，脂类的结构- 相关的或洗涤剂处理的载脂蛋白-E将被确定为定义 当载脂蛋白E从无脂的受体- 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，我们 将研究结构域相互作用对受体结合功能的影响 并测试另一组截然不同的精氨酸残基 在apo-E的铰链区内参与了受体结合活性。 拟议的研究将导致对如何在结构上 载脂蛋白-E的差异导致脂蛋白的异构体特异性效应 新陈代谢、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.