RATIONALLY DESIGNED ANALOGS OF AMPHIPATHIC HELIXES

抽象的。 这个项目的主要作用在过去，使用 两亲性α螺旋的肽类似物， 实验测试与结构相关的各种假设， 载脂蛋白的两亲性螺旋结构域的功能。 本项目的目标是继续测试新的 关于结构-功能关系的设想假设 载脂蛋白使用更复杂的实验方法 比以前使用的。 这种方法已经产生了新的 高分辨率的结构信息。 提出的具体目标 （1）开发严格的计算机算法来预测 载脂蛋白的结构与表面的 脂蛋白颗粒。 (2)血脂决定因素的研究 亲和力和LCAT活化。 (a)脂质渗透深度。 的 两亲螺旋的脂质渗透深度将是 使用荧光猝灭和中子衍射测定。 (b)不同氨基酸残基的相对疏水性。 一 将为每种氨基酸开发疏水性标度 残留物是指脂质渗透的深度。 的方法 将是测量分配系数作为螺旋位置， 客体氨基酸残基的渗透深度在 宿主两亲性α螺旋。 ~两亲分子的取向 螺旋 盘状复合物中的阻碍取向，脂质 单层和支持的脂质双层将通过 偏振衰减全反射傅里叶变换红外 谱 (3)两亲性α螺旋的结构研究 在脂质或去污剂复合物中。 (a)二维（2D）1H- 两亲性肽脂质复合物的NHR研究。 基于 根据取得的令人振奋的初步结果，我们建议 启动两亲肽的结构研究， 使用2D 1H-NMR光谱法测定脂质的存在。 (b)x射线 结晶学 与迈克尔·加拉维托博士合作， 密歇根州立大学，我们提出结晶肽 在去污剂存在下的两亲性α螺旋的类似物 和/或脂质。

Abstract. The primary role of this project in the past, using peptide analogs of the amphipathic alpha helix, has been to experimentally test various hypotheses related to the structure and function of the amphipathic helical domains of apolipoproteins. The objective of the present project is to continue testing newly conceived hypotheses regarding structure-function relationships in apolipoproteins using more sophisticated experimental methods than used previously. This approach has already yielded new high-resolution structural information. Specific aims proposed are: (1) Development of rigorous computer algorithms to predict the structure of apolipoproteins associated with the surface of lipoprotein particles. (2) Studies of the determinants of lipid affinity and LCAT activation. (a) Depth of lipid penetration. The depth of lipid penetration of amphipathic helixes will be determined using fluorescence quenching and neutron diffraction. (b) Relative hydrophobicity of different amino acid residues. A hydrophobicity scale will be developed for each amino acid residue that is indexed to depth of lipid penetration. The approach will be to measure partition coefficients as the helix position and depth of penetration of a guest amino acid residue is varied within a host amphipathic alpha helix. ~ Orientation of the amphipathic helixes. Helix orientation in the discoidal complexes, lipid monolayers and supported lipid bilayers will be determined by polarized attenuated total reflectance fourier-transform infrared spectroscopy. (3) Structural studies of amphipathic alpha helixes in lipid or detergent complexes. (a) Two dimensional (2D) 1H- NHR studies of lipid complexes of amphipathic peptides. Based upon the exciting preliminary results obtained, we propose to initiate the structural studies of the amphipathic peptides in the presence of lipid using 2D 1H-NMR spectroscopy. (b) X-ray crystallography. In collaboration with Dr. Michael Garavito of Michigan State University, we propose to crystallize peptide analogs of amphipathic alpha helixes in the presence of detergents and/or lipids.