2D IR OF UNUSUAL ISOTOPOMERS AND FOLDING

异常同位素异构体和折叠的二维红外图

• 批准号: 7598434
• 负责人: Amos B Smith
• 金额: $ 2.78万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7598434
• 关键词: Amides; Complex; Computer Retrieval of Information on Scientific Projects Database; Coupled; Coupling; Dependence; Development; Evolution; Frequencies; Funding; Grant; Institution; Isotopes; Label; Length; Measures; Methods; Molecular; Peptides; Process; Proteins; Range; Research; Research Personnel; Resolution; Resources; Source; Structure; System; Time; United States National Institutes of Health; chemical bond; infrared spectroscopy; isotope incorporation; protein folding; three dimensional structure; villin

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. To obtain a better understanding of the process of protein folding, development of physical methods that measure the time dependences of structural changes in complex systems is essential. Because of the intrinsically high time resolution, multidimensional infrared spectroscopy (2D IR and 3D IR) can contribute significantly to this challenge. IR spectra of proteins and peptides are intimately connected with their complete three-dimensional structures on the length scale of chemical bonds. However, the vibrational transitions of proteins are not always spectrally resolved. In this respect, multidimensional nonlinear infrared methods can provide additional information on how the various modes are coupled. Isotopic replacements have been essential in the interpretation of vibrational spectra and their relationship to structure. Isotopomers have frequencies, force fields, and anharmonicities that are different from one another. Incorporation of isotopes in 2D IR leads to shift in frequencies into regions where their couplings can be measured, free from interference by other modes of the system. For the amide I mode, the shifts by 13C=18O and 13C=16O substitution are sufficiently large to displace the substituted amide group frequencies beyond the range of the natural distribution of frequencies found in most secondary structures. The strategy of the Resource is to insert both 13C=18O and 13C=16O labels into secondary structures at known residues. Since their isotope shifts are different, a pair of isotopic peaks is created and 2D IR spectroscopic methods can then be used to analyze the coupling between those specific pairs of molecular transitions. Applying this approach, the real time evolution of folding of the secondary structure of the Villin headpiece can be examined using 2D IR.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 为了更好地了解蛋白质折叠过程，开发测量复杂系统中结构变化的时间依赖性的物理方法至关重要。 由于本质上具有高时间分辨率，多维红外光谱（2D IR 和 3D IR）可以为这一挑战做出重大贡献。 蛋白质和肽的红外光谱与其在化学键长度尺度上的完整三维结构密切相关。 然而，蛋白质的振动跃迁并不总是能通过光谱解析。 在这方面，多维非线性红外方法可以提供有关各种模式如何耦合的附加信息。 同位素置换对于解释振动光谱及其与结构的关系至关重要。 同位素异构体具有彼此不同的频率、力场和非谐性。 二维红外中同位素的结合导致频率转移到可以测量其耦合的区域，而不受系统其他模式的干扰。 对于酰胺 I 模式，13C=18O 和 13C=16O 取代的位移足够大，足以将取代的酰胺基团频率取代到大多数二级结构中发现的频率自然分布范围之外。 该资源的策略是将 13C=18O 和 13C=16O 标签插入已知残基的二级结构中。 由于它们的同位素位移不同，因此会创建一对同位素峰，然后可以使用二维红外光谱方法来分析这些特定分子跃迁对之间的耦合。 应用这种方法，可以使用 2D IR 检查 Villin 头盔二级结构折叠的实时演变。