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.

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 为了更好地了解蛋白质折叠的过程，发展测量复杂系统中结构变化的时间相关性的物理方法是必不可少的。由于固有的高时间分辨率，多维红外光谱(2D IR和3D IR)可以为这一挑战做出重大贡献。蛋白质和多肽的红外光谱在化学键的长度尺度上与其完整的三维结构密切相关。然而，蛋白质的振动跃迁并不总是被光谱分辨的。在这方面，多维非线性红外方法可以提供关于各种模式如何耦合的附加信息。 在解释振动光谱及其与结构的关系时，同位素置换一直是必不可少的。同分异构体具有彼此不同的频率、力场和非谐性。在2D IR中加入同位素导致频率移动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，足以取代取代的酰胺基团频率，超出了大多数二级结构中的频率自然分布范围。该资源的策略是在已知残基的二级结构中插入13C=18O和13C=16O标签。由于它们的同位素位移不同，因此产生了一对同位素峰，然后可以使用2D IR光谱方法来分析这些特定的分子跃迁对之间的耦合。应用这种方法，可以用2D IR实时检测Villin头盔二级结构的折叠演变。