RATIONALLY DESIGNED ANALOGS OF AMPHIPATHIC HELIXES

抽象的。这个项目在过去的主要作用是使用 多肽类似物的两亲性α螺旋，已经被 通过实验测试与结构和结构相关的各种假设 载脂蛋白两亲性螺旋结构域的功能。 本项目的目标是继续进行新的测试 关于结构-功能关系的设想 用更复杂的实验方法研究载脂蛋白 比以前使用的更多。这种方法已经产生了新的 高分辨率的构造信息。建议的具体目标 是：(1)开发严格的计算机算法来预测 与细胞表面相关的载脂蛋白的结构 脂蛋白颗粒。(2)脂类决定因素的研究 亲和力和LCAT激活。(A)脂质渗透深度。这个 两亲性螺旋的脂类渗透深度将是 用荧光猝灭和中子衍射法测定。 (B)不同氨基酸残基的相对疏水性。一个 将为每种氨基酸制定疏水性标尺 以脂类渗透深度为指标的残留物。该方法 将测量分配系数作为螺旋位置和 客体氨基酸残基的渗透深度在 一个宿主两亲性的阿尔法螺旋。~两亲性的定位 螺旋。盘状复合体中的螺旋取向，脂类 单层和负载型脂质双层的测定方法如下 偏振衰减全反射傅里叶变换红外 光谱学。(3)两亲性α螺旋的结构研究 在脂类或洗涤剂复合体中。(A)二维(2D)1H- 两亲性多肽类脂复合体的NHR研究。基座 在取得令人振奋的初步结果后，我们建议 启动两亲性多肽的结构研究 用2D~1H-核磁共振波谱分析脂类的存在。(B)X光检查 结晶学。与迈克尔·加拉维托博士合作 密歇根州立大学，我们提议将多肽结晶 洗涤剂存在下的两亲性α螺旋的类似物 和/或脂类。

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.