STRUCTURAL CELL BIOLOGY IN CARDIOVASCULAR DISEASE

本课程的目标是了解大分子复合体的结构生物学，这些复合体参与了脂类的进出细胞的运输。该项目的目标是：确定与低密度脂蛋白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富含甘油三酯颗粒的形成，了解N末端41%的载脂蛋白B的二级和三级结构如何调节这一过程(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，以及可交换的载脂蛋白在新生血浆高密度脂蛋白上的形成和三维结构(项目3)；了解脂肪酸与白蛋白的结合，白蛋白中脂肪酸的转移和跨膜进入细胞的运动，细胞内脂肪酸结合蛋白的结构和动态特征，以及脂肪酸对细胞内Ph的影响(项目4)。最先进的结构生物学技术被用来研究分离或重组的大分子络合物。通过结合图像分析和重建的电子显微镜，特别是低温电子显微镜，可以获得单个颗粒(和/或二维阵列)的低分辨率结构，这些结构通常装饰有特定部位的标记。通过X射线结晶学确定单个蛋白质或蛋白质-脂复合体的详细结构。模拟蛋白质或小蛋白质区域的多肽的溶液结构，如细胞内脂肪酸结合蛋白，由多维核磁共振确定。高分辨率的分子排列可以叠加在通过电子显微镜获得的大分子组件的低分辨率结构上，从而产生一个更高分辨率的大分子结构。这些研究可以提供与脂类进入细胞、细胞内和细胞外的过程有关的生物结构。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.