Peptide-Lipid Interactions--Role of Bilayer Properties

描述(申请人描述)：所有细胞膜均由 主要是蛋白质和脂类。在过去的几年里，这一点变得很明显 膜的吸附、插入、构象和功能 蛋白质都受到脂质双层基质的强烈影响。危急时刻， 膜生物学中的悬而未决的问题涉及如何组成， 双层调节肽结合的结构和力学性质 和组织能力。我们的总体目标是确定脂质介导力 影响选定的界面、跨膜和酰化的多肽和蛋白质 具有生物学意义的。我们建议将多肽的热力学联系起来 通过与双层的特定结构和材料属性结合 系统地改变双层头基，疏水厚度， 压缩模数和弯曲模数。我们的实验将使用 各种生物物理技术，包括等温滴定量热法， X射线衍射、圆二向色性、荧光光谱和直接 有约束力的分析。我们的具体目标包括：(1)测量 多肽分配到双层中的步骤，包括多肽结合， 插入和构象变化，(2)确定双分子的作用 多肽-脂类相互作用的结构和材料性质，(3)测试 目前关于多肽的形成、结构和结合的假说 脂类结构域(筏)的性质，以及(4)评估假设 蛋白质和多肽可以根据膜的长度进行分类 它们的跨膜疏水结构域或通过蛋白质棕榈酰化。这些 基础实验应该产生数据，以定量评估发表的数据 多肽脂类含能成分的理论治疗 互动，提供了关于许多类别的角色的新信息 生物膜中发现的脂类，并对其机制提供了见解 GAP-43的膜定位，GAP-43是一种对神经生长和 再生。

Description (applicant's description): All cell membranes are composed primarily of proteins and lipids. In the past few years it has become clear that the adsorption, insertion, conformation, and functioning of membrane proteins are all strongly influenced by the lipid bilayer matrix. Critical, unresolved questions in membrane biology concern how the compositional, structural, and mechanical properties of the bilayer modulate peptide binding and organization. Our overall goal is to determine how lipid-mediated forces affect selected interfacial, transmembrane, and acylated peptides and proteins of biological significance. We propose to relate the thermodynamics of peptide binding with specific structural and material properties of the bilayer by systematically varying the bilayer headgroup, hydrophobic thickness, compressibility modulus, and bending modulus. Our experiments will use a variety of biophysical techniques including isothermal titration calorimetry, X-ray diffraction, circular dichroism, fluorescence spectroscopy, and direct binding assays. Our specific aims include: (1) measuring the energetics of the steps in peptide partitioning into the bilayer, including peptide binding, insertion, and conformational changes, (2) determining the role of bilayer structure and material properties on peptide-lipid interactions, (3) testing current hypotheses concerning the formation, structure, and peptide binding properties of lipid domains (rafts), and (4) evaluating the hypothesis that proteins and peptides can be sorted in membranes on the basis of the length of their transmembrane hydrophobic domains or by protein palmitoylation. These fundamental experiments should yield data to quantitatively assess published theoretical treatments of the energetic components of peptide-lipid interactions, provide new information on the roles of the many classes of lipids found in biological membranes, and give insights on the mechanism of membrane localization of GAP-43, a protein critical to nerve growth and regeneration.