STRUCTURAL THERMODYNAMICS OF HUMAN APOLIPOPROTEIN C 1

人载脂蛋白 C 1 的结构热力学

• 批准号: 6330179
• 负责人: Olga Gursky
• 金额: $ 11.38万
• 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/6330179
• 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.

该项目的长期目标是确定分子 在可交换中限制能量结构函数关系 载脂蛋白，从而提供了对分子机制的见解 他们在动脉粥样硬化和其他的发病机理中的作用 载脂蛋白相关的疾病。可交换的载脂蛋白是水 脂质蛋白的可溶性蛋白质成分，可介导脂质和 胆固醇运输和代谢，并在 动脉粥样硬化，冠心病，中风和其他的发病机理 主要的人类疾病，包括几种形式的系统性和脑疾病 淀粉样变性。载脂蛋白对异质的结构适应性 脂蛋白复合物和血浆对于它们的血浆绝对至关重要 功能，必须被拘留以阐明 载脂蛋白作用在正常和患病中的分子机制 国家。拟议的工作通过研究解决了这一长期目标 最小人类的能量，结构和折叠途径 血浆载脂蛋白C-1（APOC-1，6 kDa）。 apoc-1的能力 激活塞丁蛋白：胆固醇酰基转移酶（LCAT）可能解释 缺乏症的受试者中胆固醇酯的正常血浆水平 主要的LCAT激活剂APOA-1。 APOC-1延迟了 通过抑制其富含动脉粥样的甘油三酸酯的颗粒 通过APOE介导的低密度低密度脂蛋白受体的吸收 相关途径。合成人的热力学和结构分析 APOC-1及其一系列针对的位点特异性突变体针对 预测的两亲α螺旋区域将通过使用 远紫外的圆形二分色谱法，差异的组合 扫描量热法和X射线衍射方法。这样的分析将1） 从部分中解剖溶液中无脂质APOC-1的折叠途径 折叠的单体折叠至完全折叠的寡聚或脂质结合状态； 2） 在单个氨基酸的水平上确定关键因素 为了稳定和合作的两亲性α-螺旋 APOC-1中的结构； 3）确定各种自我的构象APOC-1 相关状态，例如2D细丝和3D晶体，以提供模型 FIR多种功能性载脂蛋白构象。结果 该分析将为充满活力和结构的基础 了解功能性载脂蛋白反应的机制，并将 帮助了解其淀粉样生成特性，从而导致 识别各种理性治疗靶标 载脂蛋白相关的疾病。