Lipid-induced conformational switch of apolipophorin III

脂质诱导的载脂蛋白 III 构象转换

• 批准号: 6806133
• 负责人: PAUL Michiel WEERS
• 金额: $ 21.38万
• 依托单位: CALIFORNIA STATE UNIVERSITY LONG BEACH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6806133
• 关键词: SDS polyacrylamide gel electrophoresis; apolipoproteins; bacterial proteins; circular dichroism; conformation; fluorescence spectrometry; gel filtration chromatography; high performance liquid chromatography; lipid bilayer membrane; lipid metabolism; molecular pathology; phospholipids; protein binding; protein engineering; protein structure; recombinant proteins; tissue /cell culture

DESCRIPTION (provided by applicant): Exchangeable apolipoproteins play a critical role in lipoprotein metabolism. They reversibly associate with lipoprotein surfaces, and are responsible for maintaining lipid homeostasis. Apolipoproteins play an important role in cardiovascular disease but details at the molecular level are still lacking. This project aims to investigate the molecular basis of lipid binding, and gain insight in the lipid-bound conformation of the apolipoprotein. This understanding would benefit the treatment and prevention of cardiovascular disease, in particular arteriosclerosis. The present study proposes to use a well characterized invertebrate apolipoprotein as a model, apolipophorin III (apoLp-III). A combination of structural analysis (circular dichroism and fluorescence spectroscopy) and functional analysis using model phospholipid membranes will be employed. The research plan contains the following aims: (i) investigate helix bundle stability as a function of lipid binding, (ii) identification of lipid factors that trigger apolipoprotein binding, and (iii) obtaining a high resolution structure of the protein in the lipid-bound form. (i) Helix bundle stability may provide a flexible protein facilitating helix bundle opening upon lipid binding. This opening is essential as it exposes the protein's hydrophobic interior to allow direct interaction with lipid. This will be tested by engineering mutant proteins with altered stability properties, and analysis of their lipid binding properties. (ii) Not much is known about the lipid factors that trigger apolipoprotein binding. Model bilayer vesicles composed of a variety of lipids will be used to gain insight in these lipid factors. (iii) The high resolution structure of lipid-free apolipoprotein is known, but still not known for the lipid-bound form. It is crucial to gain insight in this conformation as this is the biologically active form of the protein. We aim to obtain high quality crystals of apoLp-III/phospholipid complexes that diffract at approximately 5 angstrom. This would allow visualization of individual helices, thereby gaining insight in the helix arrangement of the apolipoprotein on the lipid surface.

描述(申请人提供)：可交换的载脂蛋白在脂蛋白新陈代谢中起关键作用。它们可逆地与脂蛋白表面结合，并负责维持脂类平衡。载脂蛋白在心血管疾病中发挥着重要作用，但在分子水平上的细节仍然缺乏。本项目旨在研究脂结合的分子基础，并深入了解载脂蛋白的脂结合构象。这一认识将有助于心血管疾病，特别是动脉硬化的治疗和预防。本研究建议使用一个特性良好的无脊椎动物载脂蛋白作为模型，载脂蛋白III(apoLp-III)。将采用结构分析(圆二色谱和荧光光谱)和使用模型磷脂膜的功能分析相结合的方法。该研究计划包括以下目标：(I)研究螺旋束的稳定性作为脂结合的函数，(Ii)鉴定触发载脂蛋白结合的脂因素，以及(Iii)获得脂结合形式的蛋白质的高分辨率结构。(I)螺旋束的稳定性可以提供一种灵活的蛋白质，便于在脂类结合时打开螺旋束。这种开放是必不可少的，因为它暴露了蛋白质的疏水内部，允许与脂质直接相互作用。这将通过改变稳定特性的工程突变蛋白质和分析它们的脂结合特性来进行测试。(Ii)人们对触发载脂蛋白结合的脂质因素知之甚少。由多种脂类组成的模型双层囊泡将被用来深入了解这些脂类因素。(3)无脂载脂蛋白的高分辨结构已为人所知，但脂结合形式的高分辨结构尚不清楚。了解这种构象是至关重要的，因为这是蛋白质的生物活性形式。我们的目标是获得高质量的apoLp-III/磷脂络合物晶体，衍射率约为5埃。这将允许对单个螺旋的可视化，从而深入了解载脂蛋白在脂质表面的螺旋排列。

项目成果

Role of buried polar residues in helix bundle stability and lipid binding of apolipophorin III: destabilization by threonine 31.

埋藏极性残基在载脂蛋白 III 的螺旋束稳定性和脂质结合中的作用：苏氨酸 31 造成的不稳定。

• DOI: 10.1021/bi050502v
• 发表时间: 2005
• 期刊: Biochemistry.
• 作者: Weers,PaulMM;Abdullahi,WazirE;Cabrera,JamieM;Hsu,Tzu-Chi
• 通讯作者: Hsu,Tzu-Chi

The N-terminus of apolipoprotein A-V adopts a helix bundle molecular architecture.

• DOI: 10.1021/bi800515c
• 发表时间: 2008-08-19
• 期刊: BIOCHEMISTRY
• 影响因子: 2.9
• 作者: Wong, Kasuen;Beckstead, Jennifer A.;Lee, Dustin;Weers, Paul M. M.;Guigard, Emmanuel;Kay, Cyril M.;Ryan, Robert O.
• 通讯作者: Ryan, Robert O.