Bioorganic models for transmembrane proteins

跨膜蛋白的生物有机模型

• 批准号: 7031985
• 负责人: WILLIAM DEGRADO
• 金额: $ 28.66万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7031985
• 关键词: bacteriorhodopsins; bioenergetics; chemical models; computational biology; fluorescence resonance energy transfer; lipid bilayer membrane; membrane proteins; method development; micelles; peptide chemical synthesis; phospholamban; protein structure function; thermodynamics; water solubility

DESCRIPTION (provided by applicant): Since Anfinsen's demonstration that the sequence of a protein dictates its structure, the energetics and kinetics of folding have been explored with ever-greater temporal and spatial resolution. However, almost all of these studies have been devoted to water-soluble proteins, and our understanding of membrane proteins is in its infancy. Here, we use protein design to test and refine our understanding of membrane protein folding. Model peptides are designed to associate into helical bundles in micelles and phospholipid bilayers. The study of these systems is simplified by the fact that the unfolded state is well defined (the monomeric helices), and the energetics of folding can be monitored by measuring the monomer-nmer equilibrium. In aims 1 & 2, we test the importance and relative energetic contributions of disparate forces such as van der Waals packing versus polar interactions. These studies will not only further our understanding of protein folding, but also provide insight and methods to understand the process of transmembrane helix association, which often plays an essential role in signal transduction. As an outgrowth of our understanding of the folding of membrane proteins, we are beginning to design water-soluble versions of 2 membrane proteins, phospholamban and the KcsA potassium channel. These studies promise to provide a new method for obtaining large quantities of water-soluble versions of membrane proteins for pharmaceutical and biophysical studies. Our specific aims are as follows: Aim 1. We will study the association of designed and natural transmembrane peptides, and use these systems to understand the features leading to the folding and association of transmembrane helices. Aim 2. We will explore how regions of a protein located in the aqueous, headgroup, and membrane interior cooperate to dictate the fold of a protein by designing helical bundles that incorporate both transmembrane as well as water-soluble folding motifs. Aim 3 We will structurally characterize water-soluble versions of phospholamban and KcsA. Aim4. We will develop computational methods for transmembrane protein structure prediction & design.

描述（由申请人提供）：自从Anfinsen证明蛋白质的序列决定其结构以来，已经以更高的时间和空间分辨率探索了折叠的能量学和动力学。然而，几乎所有这些研究都致力于水溶性蛋白质，我们对膜蛋白的理解还处于起步阶段。在这里，我们使用蛋白质设计来测试和完善我们对膜蛋白折叠的理解。模型肽被设计成在胶束和磷脂双层中缔合成螺旋束。这些系统的研究被简化的事实，即未折叠状态是明确定义的（单体螺旋），折叠的能量学可以通过测量单体-单体平衡来监测。在目标1和2中，我们测试了不同力的重要性和相对能量贡献，例如货车德瓦尔斯堆积与极性相互作用。这些研究不仅将进一步加深我们对蛋白质折叠的理解，而且还为理解跨膜螺旋缔合过程提供了见解和方法，跨膜螺旋缔合通常在信号转导中起着重要作用。作为我们对膜蛋白折叠的理解的产物，我们开始设计2种膜蛋白的水溶性版本，受磷蛋白和KcsA钾通道。这些研究有望提供一种新的方法，获得大量的水溶性版本的膜蛋白的药物和生物物理研究。我们的具体目标如下：目标1。我们将研究设计和天然跨膜肽的关联，并使用这些系统来了解导致跨膜螺旋折叠和关联的特征。目标2.我们将探讨如何在水，头基，和膜内部的蛋白质的区域合作，通过设计的螺旋束，将跨膜以及水溶性折叠基序来决定蛋白质的折叠。目的3我们将在结构上表征水溶性形式的受磷蛋白和KcsA。目标4。 我们将发展跨膜蛋白质结构预测和设计的计算方法。