LIPID-MEDIATED MEMBRANE PROTEIN INSERTION AND FOLDING

描述：(逐字摘自申请者的摘要)这项工作的主要目标 项目1-继续开发耦合等离子体波导谐振(CPWR) 光谱学作为研究蛋白脂膜的重要新工具，以及 2-对膜生物物理学中的一个关键问题获得新的见解：如何 脂双分子层的物理化学性质影响插入和 将跨膜多肽螺旋组装成功能聚集体？这个 将为CPWR光谱学开发以下新功能。A--使用 不同波长分别监测脂肪和蛋白质组分 膜。这将通过脂类的发色团标记来实现，通过 在数据分析中使用光吸收系数，并通过扩展 等离子体激元的产生和探测进入近紫外区。等离子体激元的B-设计 能够同时监测CPWR频谱和电学性能的谐振器 电流流过蛋白脂膜。膜的影响 将使用结构变化来研究物理化学性质 一种人工合成的疏水螺旋小肽及其离子通道的形成 蛋白质粘附素EL。这些将被重组为固体支持的脂类 双层，其中的脂质成分可以很容易地变化。CPWR 光谱学将用于监测三个参数：A结合等温线和 多肽蛋白插入预先形成的脂质双层；b-改变 材料的折射率和光学消光系数各向异性 多肽/蛋白质结合和插入；c-在结肠素的情况下， 形成功能离子通道，如通过同时测量 CPWR光谱变化与膜电导率的动力学研究 在建立跨膜电位以启动插入之后 和航道形成。公司成立的意义和作用 非双层形成的脂类；脂类和脂类之间的疏水匹配 多肽/蛋白质；脂质堆积密度；表面电荷将 学习。这些性质会因磷脂头基团的变化而改变 同一性；脂肪酸链长；脂质堆积密度；以及 脂肪酸链不饱和。这些研究具有广泛的影响， 以膜为基础的过程在许多疾病状态下都很重要。

DESCRIPTION: (Verbatim from the Applicant's Abstract) The primary goals of this project are 1-to continue to develop coupled plasmon-waveguide resonance (CPWR) spectroscopy as an important new tool for studying proteolipid membranes, and 2-to obtain new insights into a key question in membrane biophysics: how do the physicochemical properties of the lipid bilayer influence the insertion and assembly of transmembrane peptide helices into functional aggregates? The following new capabilities will be developed for CPWR spectroscopy. a-The use of varying wavelengths to separately monitor lipid and protein components of membranes. This will be accomplished by chromophore labelling of lipids, by using the optical absorption coefficient in data analysis, and by extending plasmon generation and detection into the near UV region. b- Design of plasmon resonators that are able to simultaneously monitor CPWR spectra and electrical current flow across a proteolipid membrane. The influence of membrane physicochemical properties will be investigated using structural variations in a small synthetic hydrophobic helical peptide, and the ion-channel forming protein colicin El. These will be reconstituted into solid-supported lipid bilayers, in which the lipid composition can be readily varied. CPWR spectroscopy will be used to monitor three parameters: a- binding isotherms and peptideiprotein insertion into a preformed lipid bilayer; b- changes in refractive index and optical extinction coefficient anisotropies upon peptide/protein binding and insertion; c- in the case of colicin, the ability to form a functional ion channel, as determined by simultaneous measurements of the kinetics of CPWR spectral changes and membrane electrical conductivity subsequent to establishment of a transmembrane potential to initiate insertion and channel formation. The significance and role of the incorporation of nonbilayer-forming lipids; hydrophobic matching between lipids and peptide/proteins; lipid packing density; electrical surface charge will be studied. These properties will be varied by changes in phospholipid head group identity; fatty acid chain length; lipid packing density; and degree of unsaturation of fatty acid chains. These studies have broad implications for membrane-based processes important in many disease states.