Influence of lipids on membrane protein structure and function

脂质对膜蛋白结构和功能的影响

基本信息

批准号：
7821477
负责人：
Tamir Gonen
金额：
$ 28.21万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-05-01 至 2012-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7821477
关键词：
Address Adherens Junction Affect Binding Biological Biological Assay Biological Models C-terminal Calcium Calmodulin Cell physiology Cells Chemistry Collaborations Complex Crystalline Lens Crystallization Cytoplasm DNA Sequence Rearrangement Electrophysiology (science)Environment Face Goals Housing Intercellular Junctions Lateral Lens Fiber Ligands Lipid Bilayers Lipids Location MIP gene Mediating Membrane Membrane Biology Membrane Lipids Membrane Proteins Oocytes Permeability Physiological Proteins Recombinants Research Personnel Resolution Role Signal Transduction Structure Structure-Activity Relationship System Tail Universities Water cell type electron crystallography extracellular fiber cell insight lens oxidation periplasm professor programs protein structure function reconstitution research study response saturated fat tool two-dimensional water channel

项目摘要

DESCRIPTION (provided by applicant): In membranes, proteins and lipids form an integrated system to support essential cell functions. The structure of membrane proteins embedded in native lipid bilayers can be studied by electron crystallography. Aquaporin 0 (AQPO) is the major protein constituent in lens fiber cells where it serves a dual role: creating a pore for water and forming adhesive junctions. Using electron crystallography, we have recently determined the structure of AQPO to an unprecedented resolution of 1.9A, revealing the precise structure of a shell of ordered lipids surrounding the AQPO tetramer. AQPO therefore provides the first eukaryotic model system in which it is possible to study, in the very same membrane, the structural and functional interdependence of protein and lipids. To do this, we will form single-layered two-dimensional crystals of AQPO in lipid bilayers using native or unnatural lipids and in the presence or absence of calmodulin (CaM) which binds to the C- terminal domain of AQPO. We will then correlate the structure (from electron crystallography) and function (from electrophysiology) of the AQPO water channel as it opens and closes in response to pH, divalent calcium, and other ligands. Finally, we will also determine the structural rearrangements required for pore closure when two AQPO tetramers on separate bilayers come together to form intercellular junctions. Although this proposal addresses specific questions regarding AQPO water channel function, many of the resulting insights should be generally applicable to other channels and membrane proteins.

描述（由申请人提供）：在膜中，蛋白质和脂质形成一个集成系统来支持基本的细胞功能。嵌入天然脂质双层中的膜蛋白的结构可以通过电子晶体学来研究。水通道蛋白 0 (AQPO) 是晶状体纤维细胞中的主要蛋白质成分，具有双重作用：为水创造孔隙并形成粘合连接。使用电子晶体学，我们最近以前所未有的 1.9A 分辨率确定了 AQPO 的结构，揭示了 AQPO 四聚体周围有序脂质壳的精确结构。因此，AQPO 提供了第一个真核模型系统，可以在同一膜中研究蛋白质和脂质的结构和功能相互依赖性。为此，我们将使用天然或非天然脂质，并在存在或不存在与 AQPO C 末端结构域结合的钙调蛋白 (CaM) 的情况下，在脂质双层中形成 AQPO 的单层二维晶体。然后，我们将关联 AQPO 水通道的结构（来自电子晶体学）和功能（来自电生理学），因为它响应 pH、二价钙和其他配体而打开和关闭。最后，我们还将确定当单独双层上的两个 AQPO 四聚体聚集在一起形成细胞间连接时，孔闭合所需的结构重排。尽管该提案解决了有关 AQPO 水通道功能的具体问题，但由此产生的许多见解应该普遍适用于其他通道和膜蛋白。