STRUCTURAL CELL BIOLOGY IN CARDIOVASCULAR DISEASE

该计划的目的是了解参与脂质进出细胞运输的大分子复合物的结构生物学。该项目的目标是：确定与LDL结合的细胞受体及其配体的三维结构（项目1）：研究内质网中原始新生的富含谷胱甘肽颗粒的形成，并了解N端41% apo-B的二级和三级结构如何调控这一过程（项目2）：了解载脂蛋白B的结构和构象，低密度脂蛋白的三维结构，载脂蛋白B在低密度脂蛋白上的组织，并确定新生人血浆高密度脂蛋白上可交换载脂蛋白的形成和三维结构（项目3）;了解脂肪酸与白蛋白的结合，脂肪酸从白蛋白的转移和跨膜运动进入细胞，细胞内脂肪酸结合蛋白的结构和动力学特征，以及脂肪酸对细胞内pH的影响（项目4）。结构生物学的最新技术用于研究分离或重组的大分子复合物。通常用位点特异性标记物修饰的单个颗粒（和/或二维阵列）的低分辨率结构通过电子显微镜，特别是冷冻EM，结合图像分析和重建获得。单个蛋白质或蛋白质-脂质复合物的详细结构由X射线晶体学确定。通过多维NMR确定模拟蛋白质或小蛋白质（例如细胞内脂肪酸结合蛋白质）区域的肽的溶液结构。高分辨率分子排列可以叠加到通过电子显微镜获得的大分子组装体的低分辨率结构上，以产生“更高分辨率”的大分子结构。这些研究可以提供脂质移入、移入和移出细胞的过程中所涉及的生物结构。这些信息将允许开发新的基于分子的策略来控制高β脂蛋白血症、脂肪酸诱导的缺血细胞损伤和动脉硬化。

The objective of this program is to understand the Structural Biology of the macromolecular complexes involved in the transport of lipids into and out of cells. The aims of the project are: to define the 3-dimensional structures of cellular receptors and their ligands bound to LDL (Project 1): to study the formation of primordial nascent triglyceride-rich particles in the endoplasmic reticulum and understand how the secondary and tertiary structures of the N-terminal 41% apo-B regulates this process (Project 2); to understand the structure and conformation of apo-B, the 3- dimensional structure of LDL, the organization of apo-B on LDL, and to define the formation and 3-dimensional structure of exchangeable apolipoproteins on nascent ans plasma HDL (Project 3); to understand the binding of fatty acids to albumin, the transfer of fatty acids from albumin and movement across membranes into cells, structural and dynamic features of intracellular fatty acid binding proteins, and the effect of fatty acids on intracellular Ph (Project 4). State-of-the-art techniques of structural biology are used to study isolated or reconstituted macromolecular complexes. Low resolution structures of individual particles (and/or 2 dimensional arrays) often decorated with site specific labels are obtained by electron microscopy, in particular cryo-EM, combined with image analysis and reconstruction. Detailed structures of individual proteins or protein-lipid complexes are determined by x-ray crystallography. The solution structure of peptides that model regions of proteins or small proteins such as the intracellular fatty acid binding proteins are determined by multi-dimensional NMR. High resolution molecular arrangements can be superimposed onto the low resolution structure of macromolecular assemblies obtained by electron microscopy to generate a "higher resolution" macromolecular structure. These studies can provide the biological structures involved in the processes by which lipids are moved into, within, and out of cells. Such information will allow the development of new molecular based strategies to control hyper beta lipoproteinemia, fatty acid-induced cellular damage in ischemia, and arteriosclerosis.