DYNAMIC EXCHANGE IN SLOWLY RELAXING LOCAL STRUCTURE MODEL

缓慢松弛局部结构模型中的动态交换

• 批准号: 8363974
• 负责人: ZHICHUN LIANG
• 金额: $ 1.63万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8363974
• 关键词: Exhibits; Frequencies; Funding; Grant; Modeling; Motion; Muramidase; National Center for Research Resources; Principal Investigator; Probability; Process; Proteins; Research; Research Infrastructure; Resources; Site; Source; Spin Labels; Structure; Technology; Time; United States National Institutes of Health; conformer; cost; mutant; research study

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Recent multifrequency ESR studies of spin labeled mutants of T4-lysozyme have shown the existence of two spectral components that have been tentatively ascribed to the existence of more than one stable conformer of the nitroxide tether of the MTSSL spin label. These multifrequency experiments have previously been analyzed by the slowly-relaxing local structure (SRLS) model that includes as distinct entities the overall motion of the protein and the local motion sensed by the spin label. Results at the different frequencies have suggested that there may be a dynamic exchange occurring between the two conformers, such that the spectral effects of the exchange depends on the ESR frequency studied. Dynamic exchange has now been incorporated into the SRLS model, wherein each conformer has its own overall and local rotational dynamics and orienting potential. The exchange process is characterized by the probability of each site and the mean exchange rate. We have studied, in particular, the effects of dynamic exchange for the case of two sites, wherein both sites exhibit very slow overall tumbling, but Site 1 exhibits relatively fast local motion and low local ordering, whereas Site 2 exhibits slow local motion and high local ordering. Due to their different time scales, ESR spectra taken at the higher (lower) frequencies are sensitive to faster (slower) exchange processes.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。 列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 最近对T4-淋巴染的自旋标记突变体的多频ESR研究表明，存在两个光谱成分，这些光谱成分暂时归因于MTSSSL自旋标记的硝基氧化物扎件的一个以上稳定的构象异构体的存在。这些多频实验先前已经通过缓慢省力的局部结构（SRLS）模型进行了分析，该模型包括作为不同实体的蛋白质的整体运动和自旋标记感知的局部运动。在不同频率的结果表明，两个构象异构体之间可能发生动态交换，因此交换的光谱效应取决于所研究的ESR频率。 现在将动态交换纳入了SRLS模型中，其中每个构象异构体都有其自身和局部旋转动力学和定向潜力。交换过程的特征是每个站点的概率和平均汇率。我们已经研究了两个站点的动态交换的影响，其中两个站点的总体滚动表现非常缓慢，但是站点1表现出相对较快的局部运动和较低的本地订购，而Site 2则表现出缓慢的本地运动和较高的本地订购。由于其时间尺度不同，ESR光谱在较高（较低）的频率上对更快（较慢）的交换过程敏感。