STRUCTURAL STUDIES OF LIPID/ PROTEIN SYSTEMS

脂质/蛋白质系统的结构研究

• 批准号: 2168795
• 负责人: LEONARD J. BANASZAK
• 金额: $ 37.21万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-05-01 至 1999-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2168795
• 关键词: Agnatha; X ray crystallography; apolipoproteins; chemical binding; computer simulation; conformation; crystallization; egg /ovum; fatty acid binding protein; high density lipoproteins; lipid transport; mutant; nonblood lipoprotein; physical model; protein purification; protein reconstitution; protein structure function; retinoid binding proteins; site directed mutagenesis; steroid hormone receptor; structural biology; thermodynamics; vitellin

X-ray crystallography will be used to study the molecular structure of lipid:protein complexes ranging from extracellular proteins such as lipovitellin and apo Al to small intracellular lipid binding proteins. All the studies play a role in understanding the stabilization of lipid in an aqueous environment along with associated health related problems which involve the transient flux of lipids. Lipovitellin from lamprey oocytes is one of the crystalline proteins. It contains 15% w/w of lipid. The present model, though incomplete, has been obtained by x-ray and neutron diffraction data. The current focus is the assignment of the amino acid sequence to the electron density map. A second study will involve crystallographic studies of both apo Al, a constituent of HDL, and reconstituted apo Al :lipid particles. Using an existing form of recombinant proapo Al, a new expression system will eliminate the "pro" piece and add five histidine residues to the carboxy-terminal. This will permit a simple and large scale purification protocol. Another aspect of the studies focusses on a family of intracellular lipid binding proteins which are responsible for the translocation of fatty acids and retinoids within the cell. The background studies have shown that the hydrophobic compound is contained within an internalized water filled cavity.. Site- directed mutagenesis and crystallography will be used to gate ligand binding and to alter the internalized structured water. A protein which binds retinoic acid in a manner analogous to the fatty acid and retinol binding proteins will be analyzed by x-ray crystallography. The fourth and last study involves the purification and crystallization of the ligand binding domain of the nuclear receptor protein, RXR. The receptors for vitamin A analogues (RXR and RAR) play a dominant role in the development of a body plan as shown by teratogenic effects in embryos. These hormonal properties are the result of effects on the transcriptional rates of special targeted genes. Although structural studies on the segment of the protein which binds to DNA hake been completed, no three dimensional data on the retinoic acid-binding domain is available. Studies of RXR are closely related to those of the intra- cellular retinoic acid binding protein mentioned above.

X射线晶体学将用于研究分子结构 脂质：蛋白质复合物，包括细胞外蛋白质，例如 lipovitellin 和 apo A1 与小细胞内脂质结合蛋白。 所有的研究都有助于了解脂质的稳定性 在水环境中以及相关的健康相关问题 其中涉及脂质的瞬时通量。来自七鳃鳗的卵黄素 卵母细胞是晶体蛋白之一。它含有 15% w/w 脂质。目前的模型虽然不完整，但已通过 X 射线获得 和中子衍射数据。当前的重点是分配 氨基酸序列到电子密度图。第二项研究将 涉及载脂蛋白Al（HDL 的组成部分）的晶体学研究， 和重构apo Al：脂质颗粒。使用现有的形式 重组proapo Al，新的表达系统将消除“pro” 片并在羧基末端添加五个组氨酸残基。这将 允许简单且大规模的纯化方案。另一个方面 该研究重点关注细胞内脂质结合蛋白家族 负责脂肪酸和类视黄醇的易位 细胞内。背景研究表明，疏水性 化合物包含在内部充满水的空腔内。 定向诱变和晶体学将用于选通配体 结合并改变内化的结构水。 一种蛋白质，其中 以类似于脂肪酸和视黄醇的方式结合视黄酸 结合蛋白将通过 X 射线晶体学进行分析。第四个 最后的研究涉及纯化和结晶 核受体蛋白 RXR 的配体结合域。这 维生素 A 类似物受体（RXR 和 RAR）在 身体计划的发展如致畸效应所示 胚胎。这些荷尔蒙特性是影响的结果 特殊目标基因的转录率。虽然是结构性的 对与 DNA 结合的蛋白质片段的研究已经 已完成，没有视黄酸结合域的三维数据 可用。 RXR 的研究与内部的研究密切相关。 上述细胞视黄酸结合蛋白。