BIOORGANIC MODELS FOR TRANSMEMBRANE PROTEINS

描述：(申请人的摘要)管理折叠和 膜蛋白的功能比水溶蛋白的功能了解得更少。 一个。因此，虽然有大量关于相关自由能的数据 非极化群的埋葬或氢键在 水溶性蛋白质，这种数据对于膜来说几乎是不存在的 蛋白质。我们将确定膜上的氨基酸取代是如何 蛋白质细菌视紫红质影响其稳定自由能。一直以来 假设虽然水溶蛋白和膜蛋白有很大不同 在亲水残基和膜亲脂残留物的极性上，它们的 内部侧链堆积和残基的极性非常相似。为了测试 在这个指导性假设中，我们将把水溶性蛋白质转化为 膜可溶蛋白质，反之亦然。因此，我们的具体目标是： -目的1.水溶性卷曲多肽的膜可溶形式， GCN4-P1将在胶束和 双层的。 -目标2.我们将确定氨基酸取代对 细菌视紫红质的热力学稳定性。 -目标3。我们将设计和表征一种水溶性版本的 磷蛋白，一种形成跨膜的57个残基的膜蛋白 五聚体。在每种情况下，蛋白质的热力学性质将是 彻底检查，以提供对膜的更深入、定量的了解 蛋白质结构。

Description: (Applicant's abstract) The energetics governing the folding and function of membrane proteins is less well understood than for water-soluble ones. Thus, while there are abundant data concerning the free energy associated with the burial of an apolar group or the formation of a hydrogen bond in water-soluble proteins, such data are virtually non-existent for membrane proteins. We will determine how amino acid substitutions in the membrane protein bacteriorhodopsin affect its free energy of stabilization. It has been hypothesized that although water-soluble and membrane proteins differ greatly in the polarity of water-facing versus membrane lipid-facing residues, their interior side-chain packing and residue polarities are highly similar. To test this guiding hypothesis we will convert water-soluble proteins into membrane-soluble proteins and vice versa. Our specific aims, then, are: - Aim 1. Membrane-soluble versions of the water-soluble coiled-coil peptide, GCN4-P1, will be designed, synthesized and characterized in micelles and bilayers. - Aim 2. We will determine the effect of amino acid substitutions on the thermodynamic stability of bacteriorhodopsin. - Aim 3. We will design and characterize a water-soluble version of phospholamban, a 57-residue membrane protein that forms transmembrane pentamers. In each case, the thermodynamic properties of the proteins will be thoroughly examined to provide a deeper, quantitative understanding of membrane protein structure.