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.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的首席研究员可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 最近对 T4-溶菌酶自旋标记突变体的多频 ESR 研究表明，存在两种光谱成分，这两种成分暂时归因于 MTSSL 自旋标签的硝基氧系链存在多个稳定构象异构体。这些多频率实验之前已通过缓慢松弛局部结构（SRLS）模型进行了分析，该模型包括蛋白质的整体运动和自旋标签感知的局部运动作为不同的实体。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。 动态交换现已纳入 SRLS 模型，其中每个构象异构体都有自己的整体和局部旋转动力学和定向潜力。交换过程用每个站点的概率和平均交换率来表征。我们特别研究了动态交换对两个站点情况的影响，其中两个站点都表现出非常缓慢的整体翻滚，但站点 1 表现出相对较快的局部运动和较低的局部排序，而站点 2 表现出较慢的局部运动和较高的局部运动。本地订购。由于时间尺度不同，在较高（较低）频率下获取的 ESR 谱对较快（较慢）的交换过程很敏感。