Understanding Beta-Sheet Structure in Aqueous Solution

了解水溶液中的β-片层结构

• 批准号: 6910847
• 负责人: JEFFERY W KELLY
• 金额: $ 29.7万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6910847
• 关键词: analytical ultracentrifugation; chemical models; circular dichroism; fluorescence resonance energy transfer; hydrogen bond; infrared spectrometry; interferometry; mass spectrometry; model design /development; nuclear magnetic resonance spectroscopy; peptide chemical synthesis; protein folding; protein structure; synthetic peptide; thermodynamics; water solution

DESCRIPTION (provided by applicant): The long term objective of this research is to understand the structural principles of beta-sheet folding using a small protein that folds by a two state mechanism. We utilize sequences of the Pin WW domain, a 34 residue 3-stranded antiparallel Beta-sheet, incorporating both natural and unnatural amino acid mutations to understand the structural features that are critical for the transition state formation and ground state stability. Our ability to chemically synthesize WW domains with varied backbone connectivity and a constant Beta-sheet core structure allows us to understand what aspect of topology (structure) is important for predicting folding rates-a prediction that is accurate within an order of magnitude or so. Synthetic accessibility also allows us to make subtle changes in WW domain structure to better understand how these changes influence the range of folding rates exhibited by WW domain variants. Thermodynamic and kinetic data for mutations at nearly every position in the sequence can be processed to afford a Phi (phi) analysis (phi) = deltadeltaG++/deltadeltaG) to discern the extent to which a perturbation in the free energy of folding is mirrored in the transition state. We make predictions about the importance of certain structural features including hydrogen bonding, hydrophobic interactions, conformational preferences, chain connectivity (topology), etc. in both the ground state and transition states that can be tested experimentally using a phi analysis. Understanding Beta-sheet folding is important to improve fold predictions from sequence and to begin to understand the balance between 13-sheet folding and misfolding-the latter process affords aggregates that appear to cause neurodegeneration.

描述（由申请人提供）：本研究的长期目标是了解使用通过两种状态机制折叠的小蛋白质进行 β-折叠折叠的结构原理。我们利用 Pin WW 结构域（一种 34 个残基的 3 链反平行 Beta 片层）的序列，结合天然和非天然氨基酸突变来了解对于过渡态形成和基态稳定性至关重要的结构特征。我们能够化学合成具有不同主干连接性和恒定 Beta 片层核心结构的 WW 结构域，这使我们能够了解拓扑（结构）的哪些方面对于预测折叠率很重要，这种预测在一个数量级左右是准确的。合成可访问性还允许我们对 WW 域结构进行细微的改变，以更好地了解这些变化如何影响 WW 域变体所表现出的折叠率范围。序列中几乎每个位置的突变的热力学和动力学数据都可以进行处理，以提供 Phi (phi) 分析 (phi) = deltadeltaG++/deltadeltaG)，以辨别折叠自由能的扰动在过渡态中的反映程度。我们对基态和过渡态中某些结构特征的重要性进行预测，包括氢键、疏水相互作用、构象偏好、链连接性（拓扑）等，可以使用 phi 分析进行实验测试。了解 Beta-sheet 折叠对于改进序列折叠预测并开始了解 13-sheet 折叠和错误折叠之间的平衡非常重要 - 后者过程提供了似乎导致神经退行性变的聚集体。