BIOORGANIC MODELS FOR TRANSMEMBRANE PROTEINS

描述：（申请人的摘要）控制折叠的能量学和 膜蛋白的功能不如水溶性蛋白那么清楚 一个因此，虽然有大量的数据有关的自由能相关 随着非极性基团的埋藏或氢键的形成， 水溶性蛋白质，这样的数据几乎不存在膜 proteins.我们将确定细胞膜上的氨基酸替换 蛋白质细菌视紫红质影响其稳定化自由能。已经 假设虽然水溶性蛋白和膜蛋白有很大的不同， 在极性的水面对与膜脂面对的残基，其 内部侧链堆积和残基极性高度相似。测试 这个指导性假设，我们将把水溶性蛋白质转化为 膜溶性蛋白质，反之亦然。因此，我们的具体目标是： - 目标1。水溶性卷曲螺旋肽的膜溶性形式， GCN 4-P1将在胶束中设计、合成和表征， 双层。 - 目标二。我们将确定氨基酸取代对细胞的影响。 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的 受磷蛋白，一种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，以提供更深入的，定量的了解膜 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.