BETA SHEET FORMATION IN A SIMPLE MODEL SYSTEM

描述：这项拟议的研究试图理解能量学和 B片式结构的设计。里根博士已经成功地开发出一种模型 基于b1的变体来研究b-Sheet形成的系统 Ig G结合蛋白结构域(B1)。B1在结构上是一种 热力学很好地表征了56个残基蛋白。她很容易就能 操纵编码它的基因，提纯大量的蛋白质。 在初步研究中，通过在溶剂中进行一系列取代 暴露的位置，她已经确定了一个热力学标度 氨基酸的B-片层形成倾向。建立在这些基础上 发现，她还测量了两人之间相互作用的能量学 H键反平行b-折叠的两条链上的氨基酸 地点。她的实验结果与统计学有很强的相关性。 派生概率。 在目前的提案中，她继续执行另外两个 成对研究：一个非氢键反平行中心和一个氢键 平行站点。在这些地点统计观察到的配对是 与她最初的研究有很大的不同。她会跟着来的 在这项工作的基础上，使用核磁共振方法对自然进行结构表征 稳定的相互作用。 最后，她将追求新颖的设计，以解决特殊性与 蛋白质结构的稳定性，通过将b-折叠转化为a-螺旋和副链 反过来说。第一个这样的设计已经实现：一种具有50 与b1的同源性百分比，但采用螺旋构象。进一步 这样的设计及其结构和热力学特性是 建议。 她的研究成果将极大地提高基础 了解B形薄板结构的受力和设计，并铺设 合理重新设计b形薄板的基本规则。

DESCRIPTION: The proposed research seeks to understand the energetics and design of b-sheet structure. Dr. Regan has successfully developed a model system in which to study b-sheet formation, based on a variant of the b1 domain of IgG-binding protein G (b1). b1 is a structurally and thermodynamically well characterized 56 residue protein. She can readily manipulate the gene that encodes it and purify large quantities of protein. In preliminary studies, by making a series of substitutions at solvent exposed positions, she has determined a thermodynamic scale for the b-sheet-forming propensities of the amino acids. Building on these findings, she also measured the energetics of pair-wise interactions between amino acids across two strands of an anti-parallel b-sheet at an H-bonded site. Her experimental results show strong correlations with statistically derived probabilities. In the current proposal, she goes forward to perform two additional pair-wise studies: a non-H-bonded anti-parallel site and an H-bonded parallel site. The statistically observed pairings at such sites are significantly different from those of her original study. She will follow up on this work by using NMR methods to structurally characterize the nature of the stabilizing interactions. Finally, she will pursue novel designs to address specificity versus stability in protein structure, by converting b-sheet into a-helix and vice versa. The first such design has been realized: a protein that has 50 percent identity to b1, but which adopts a helical conformation. Further such designs and their structural and thermodynamic characterization are proposed. The results of her studies will significantly enhance fundamental understanding of the energetics and design of b-sheet structure and lay the ground rules for the rational redesign of b-sheets.