Peptide-Lipid Interactions--Role of Bilayer Properties

描述（申请人描述）：所有细胞膜均由 主要是蛋白质和脂质。在过去的几年里， 膜的吸附、插入、构造和功能 蛋白质都受到脂质双层基质的强烈影响。很关键， 膜生物学中尚未解决的问题涉及组成， 结构和机械性能的双层调节肽结合 和组织。我们的总体目标是确定脂质介导的力量 影响选定的界面、跨膜和酰化肽和蛋白质 具有生物学意义。我们建议将肽的热力学 与双层的特定结构和材料性质结合， 系统地改变双层头基，疏水厚度， 压缩模量和弯曲模量。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、圆二色性、荧光光谱和直接 结合测定。我们的具体目标包括：（1）测量能量的 肽分配到双层中的步骤，包括肽结合， 插入和构象变化，（2）确定双层的作用 结构和材料性质对肽-脂质相互作用的影响，（3）测试 目前关于形成、结构和肽结合的假说 脂质结构域（筏）的性质，和（4）评估假设， 蛋白质和肽可以在膜中根据蛋白质的长度进行分选。 它们的跨膜疏水结构域或通过蛋白质棕榈酰化。这些 基础实验应产生数据，以定量评估已发表的 肽-脂含能组分的理论处理 互动，提供新的信息的作用，许多类的 生物膜中发现的脂质，并提供关于 GAP-43是一种对神经生长至关重要的蛋白质， 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.