STRUCTURAL THERMODYNAMICS OF HUMAN APOLIPOPROTEIN C 1

人载脂蛋白 C 1 的结构热力学

• 批准号: 6125976
• 负责人: Olga Gursky
• 金额: $ 10.93万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-12-15 至 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6125976
• 关键词: X ray crystallography; amphiphilicity; apolipoproteins; calorimetry; chemical models; chemical stability; circular dichroism; conformation; crystallization; protein folding; protein sequence; protein structure function; site directed mutagenesis; structural biology; synthetic protein; thermodynamics

The long-term objective of this project is to determine in molecular detain the energetic-structure-function relationship in exchangeable apolipoproteins, thereby providing an insight into molecular mechanisms of their action in the pathogenesis of atherosclerosis and other apolipoprotein-related disorders. Exchangeable apolipoproteins are water- soluble protein components of lipoproteins that mediate lipid and cholesterol transport and metabolism and play crucial roles in the pathogenesis of atherosclerosis, coronary heart disease, stroke, and other major human disorders including several forms of systemic and cerebral amyloidosis. Structural adaptability of apolipoproteins to heterogenous lipoprotein complexes and to plasma is absolutely essential for their functions, and has to be understood in detain in order to elucidate molecular mechanisms of apolipoprotein action in normal and in diseased states. The proposed work addresses this long-term goal through studies of the energetics, structure and folding pathway of the smallest human plasma apolipoprotein C-1 (apoC-1, 6 kDa). The ability of apoC-1 to activate lecitin: cholesterol acyltransferase (LCAT) may account for normal plasma levels of cholesterol esters in subjects with deficiency of the major LCAT activator, apoA-1. ApoC-1 delays the clearance of potentially atherogenic triglyceride-rich particles by inhibiting their uptake via the apoE-mediated low-density low-density lipoprotein receptor- related pathway. Thermodynamic and structural analyses of synthetic human apoC-1 and a series of its site-specific mutants targeted towards the predicted amphipathic alpha-helical regions will be carried out by using a combination of far-UV circular dichroism spectroscopy, differential scanning calorimetry, and x-ray diffraction methods. Such analysis will 1) dissect the folding pathway of lipid-free apoC-1 in solution, from partly folded monomeric to fully folded oligomeric or lipid-bound state; 2) determine, at the level of individual amino acids, the critical factors for the stability and cooperatively of the amphipathic alpha-helical structure in apoC-1; 3) determine the conformation apoC-1 in various self- associated status, such as 2D filaments and 3D crystals, to provide models fir a variety of functional apolipoprotein conformations. The results of this analysis will provide the energetic and structural basis for understanding mechanisms of functional apolipoprotein reactions and will help to understand their amyloidogenic properties, thereby leading to identification of rational therapeutic targets in a variety of apolipoprotein-related disorders.

这个项目的长期目标是确定分子中的 在可交换材料中保留能量-结构-功能关系 载脂蛋白，从而提供了一个洞察的分子机制 它们在动脉粥样硬化和其他疾病的发病机制中的作用 载脂蛋白相关疾病。可交换的载脂蛋白是水- 脂蛋白的可溶性蛋白质组分，调节脂质和 胆固醇的运输和新陈代谢，并在 动脉粥样硬化、冠心病、中风等的发病机制 人类的主要疾病包括几种形式的系统性和脑部疾病 淀粉样变性。载脂蛋白对异源基因的结构适应性 脂蛋白复合体和到血浆是绝对必要的 职能，并必须在拘留期间理解，以便澄清 载脂蛋白在正常和疾病中作用的分子机制 各州。拟议的工作通过研究解决了这一长期目标 关于最小的人类的能量、结构和折叠路径 血浆载脂蛋白C-1(apoC-1，6 kDa)。载脂蛋白C-1的功能 激活卵磷脂：胆固醇酰基转移酶(LCAT)可能是 缺铁性贫血患者血浆胆固醇酯正常水平的研究 LCAT的主要激活因子apoA-1。载脂蛋白C-1推迟清理 可能导致动脉粥样硬化的富含甘油三酯的颗粒 通过载脂蛋白E介导的低密度脂蛋白受体摄取- 相关途径。人工合成人体的热力学和结构分析 ApoC-1及其一系列靶向于 预测的两亲性α-螺旋区域将通过使用 远紫外圆二色光谱的组合，差示 扫描量热法和x射线衍射法。这样的分析将1) 解剖脱脂apoC-1在溶液中的折叠途径，从部分 折叠单体到完全折叠的齐聚物或脂结合状态；2) 在单个氨基酸水平上确定关键因素 两亲性α-螺旋的稳定性和协同性 ApoC-1的结构；3)决定apoC-1在不同自身 关联状态，如2D细丝和3D晶体，以提供模型 有多种功能的载脂蛋白构象。结果是 这一分析将提供能量和结构基础 了解功能性载脂蛋白反应和意志的机制 有助于了解它们的淀粉样蛋白致病特性，从而导致 多种疾病合理治疗靶点的确定 载脂蛋白相关疾病。