The structural basis for cholesterol esterification in human plasma

人血浆中胆固醇酯化的结构基础

• 批准号: 10028460
• 负责人: W Sean Davidson
• 金额: $ 49.8万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10028460
• 关键词: Address; Apolipoprotein A-I; Apolipoprotein A-II; Apolipoprotein E; Apolipoproteins; Apolipoproteins B; Attenuated; Binding; Binding Sites; Biological Assay; Blood Circulation; Brain; Cardiovascular Diseases; Chemicals; Cholesterol; Cholesterol Esters; Complex; Cryoelectron Microscopy; Crystallization; Deposition; Disease; Docking; Electron Microscopy; Epitopes; Equilibrium; Esterification; Face; Fatty Acids; Fatty acid glycerol esters; Fluorescence; Genetic; Genetic Diseases; High Density Lipoproteins; Human; Image; Individual; Inflammatory; Kidney Failure; Knowledge; Laboratories; Lecithin; Lipids; Lipoproteins; Location; Low-Density Lipoproteins; Mass Spectrum Analysis; Mediating; Metabolism; Molecular; Molecular Conformation; Mutagenesis; Nucleosome Core Particle; Organ; Participant; Peptides; Phospholipase; Plasma; Play; Production; Proteins; Reaction; Recombinants; Registries; Roentgen Rays; Role; Running; Scientist; Series; Site; Site-Directed Mutagenesis; Structural Models; Structure; Surface; Surface Plasmon Resonance; System; Testing; Therapeutic; Transferase; Translating; Triglycerides; Very low density lipoprotein; Work; cofactor; crosslink; design; experimental study; fish eye disease; interest; novel; particle; tool

Lecithin:cholesterol acyl transferase (LCAT) catalyzes the esterification of a fatty acid to cholesterol and is responsible for the majority of cholesteryl ester (CE) in the human circulation. Its activity is dramatically enhanced by cofactor apolipoproteins such as apolipoprotein (apo)A-I in HDL and apoE in LDL/VLDL and brain lipoproteins. While this cofactor relationship has been known for decades, our understanding of how apolipoproteins activate LCAT remains limited. Our preliminary work has shown that LCAT interacts with two mirror image docking sites within apoA-I that are composed of helix 4 in one apoA-I molecule and helix 6 of the opposing molecule. When this registry is disrupted, LCAT can still bind HDL but no longer catalyzes CE formation. We hypothesize that these docking sites orient LCAT with respect to the lipid faces of HDL particles and may form a conduit by which the particle core is accessed for deposition of CE. Additionally, we suspect that these sites direct the cholesterol substrate to the site of LCAT interaction via specific recognition sequences. We also believe that apoA-II, another highly abundant HDL apolipoprotein, disrupts this interaction to reduce LCAT activity. Leveraging new experimental tools developed in our laboratory, we will; 1) define the molecular mechanism for apoA-I activation of LCAT and the role of these interaction sites, 2) determine how apoA-II attenuates the LCAT reaction and 3) define the mechanism behind apoE stimulation of LCAT. This work will answer nearly 50 year old questions about how apolipoproteins enhance LCAT’s ability mediate plasma cholesterol esterification. In addition, we will translate this knowledge into the design of novel bi-helical peptides that may form a basis for treating individuals with genetic partial deficiencies of LCAT activity such as Fish Eye Disease (FED).

卵磷脂：胆固醇酰基转移酶（LCAT）催化脂肪酸酯化， 胆固醇，是人体中大部分胆固醇酯 (CE) 的来源 其活性可通过辅因子载脂蛋白（例如）显着增强。 HDL 中的载脂蛋白 (apo)A-I 和 LDL/VLDL 中的 apoE 以及脑脂蛋白。 辅因子关系已为人所知数十年，我们对载脂蛋白如何理解 我们的初步工作表明 LCAT 与两个相互作用。 apoA-I 内的镜像对接位点由一个 apoA-I 分子中的螺旋 4 组成 当这个注册被破坏时，LCAT仍然可以结合HDL。 但不再催化 CE 形成 我们发现这些对接位点定向 LCAT。 相对于 HDL 颗粒的脂质面，并且可以形成管道，颗粒通过该管道 另外，我们怀疑这些站点直接访问了核心以进行 CE 沉积。 通过特定识别序列将胆固醇底物连接至 LCAT 相互作用位点。 还相信另一种高丰度 HDL 载脂蛋白 apoA-II 会破坏这种作用 利用我们开发的新实验工具来减少 LCAT 活性。 实验室，我们将；1) 定义 LCAT 和 apoA-I 激活的分子机制 这些相互作用位点的作用，2) 确定 apoA-II 如何减弱 LCAT 反应，3) 定义 LCAT 的 apoE 刺激背后的机制 这项工作将回答近 50 年的问题。 关于载脂蛋白如何增强 LCAT 介导血浆胆固醇能力的老问题 此外，我们将把这些知识转化为新型双螺旋的设计。 可能构成治疗 LCAT 遗传性部分缺陷个体的基础的肽 鱼眼病 (FED) 等活动。