PROBING THE FOLDING TRANSITION STATE VIA SIDECHAIN AND BACKBONE MUTATIONS

通过侧链和主链突变探测折叠过渡状态

• 批准号: 7723861
• 负责人: JEFFERY A KELLEY
• 金额: $ 0.52万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7723861
• 关键词: Address; Amides; Computer Retrieval of Information on Scientific Projects Database; Esters; Funding; Grant; Institution; Kinetics; Length; Molecular Conformation; Mutate; Mutation; Object Attachment; Oxygen; Peptides; Proteins; Rate; Research; Research Personnel; Resources; Role; Rotation; Side; Source; Structure; Testing; Thermodynamics; United States National Institutes of Health; Vertebral column; Work; beta pleated sheet; mutant; protein folding; tool

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Backbone-backbone H-bonds are prominent features of the structures of beta-sheets. Because of their central role in this ubiquitous secondary structure, we will determine the contribution backbone-backbone H-bond formation in general, and beta-turn formation in particular, to the kinetics of beta-sheet formation. This will be accomplished using a Phi(M)-value analysis of amide-to-ester mutants of a well-studied beta-hairpin peptide. The contribution of backbone-backbone H-bonds to the thermodynamics and kinetics of protein folding in general, and beta-sheet folding in particular, is controversial. Previously, we used amide-to-ester mutations, in which a backbone amide is replaced by an ester, to address this problem. Amide-to-ester mutation is a powerful tool for studying backbone-backbone H-bonding in proteins because (1) esters and amides have similar bond lengths and angles; (2) esters and amides both have a high barrier to rotation and favor a trans conformation about the C'-Oe or C'-NH bond ("Oe" refers to the non-carbonyl oxygen in an ester); and (3) amide-to-ester mutations do not alter the intrinsic conformational propensity or side chain interactions of the mutated residue because the side chain is not altered. Many studies, including our own work on the Pin WW domain, have suggested the hypothesis that turn formation limits the folding rate of beta-hairpins and small beta-sheet proteins. To better understand this fundamental aspect of beta-sheet folding, this hypothesis will be tested by using Phi(M)-value analysis of amide-to-ester mutations on a beta-hairpin and/or alpha-helical peptides.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 骨架-骨架氢键是β-折叠结构的突出特征。 由于它们在这种无处不在的二级结构中的中心作用，我们将确定骨架-骨架H-键形成的贡献，特别是β-转角形成对β-折叠形成动力学的贡献。 这将使用充分研究的β-发夹肽的酰胺-酯突变体的Phi（M）-值分析来实现。骨架-骨架氢键对蛋白质折叠的热力学和动力学的贡献，特别是β折叠，是有争议的。 以前，我们使用酰胺到酯的突变，其中骨架酰胺被酯取代，以解决这个问题。 酰胺-酯突变是研究蛋白质骨架-骨架氢键的有力工具，因为（1）酯和酰胺具有相似的键长和键角;（2）酯和酰胺都具有高的旋转势垒，有利于C '-Oe或C'-NH键的反式构象（“Oe”是指酯中的非羰基氧）;和（3）酰胺-酯突变不改变突变残基的固有构象倾向或侧链相互作用，因为侧链没有改变。许多研究，包括我们自己对Pin WW结构域的研究，都提出了这样的假设，即转角形成限制了β-发夹和小β-折叠蛋白的折叠速率。 为了更好地理解β-折叠的这个基本方面，将通过使用β-发夹和/或α-螺旋肽上的酰胺至酯突变的Phi（M）-值分析来测试该假设。