MULTIFREQUENCY ESR STUDIES OF PROTEIN DYNAMICS T4 LYSOZYME

T4 溶菌酶蛋白质动力学的多频 ESR 研究

• 批准号: 8363927
• 负责人: KEITH A EARLE
• 金额: $ 0.46万
• 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/8363927
• 关键词: Affect; Appearance; Complex; Coupling; Disease model; Frequencies; Funding; Grant; Label; Maps; Microscopic; Modeling; Muramidase; Mutagens; National Center for Research Resources; Noise; Principal Investigator; Protein Dynamics; Proteins; Research; Research Infrastructure; Resources; Signal Transduction; Site; Source; Spectrum Analysis; Spin Labels; Structure; System; Technology; Temperature; Time; United States National Institutes of Health; base; cost; improved; insight; macromolecule; 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. A multifrequency approach combining high and low ESR frequencies can enable a decomposition of the complex dynamic modes affecting each site label on a protein labeled via site-directed spin-labeling (SDSL). In a recent study on T4 lysozyme using mutagens, to which a spin label is attached at different residues, we showed that the high-field/high-frequency-ESR (HFHF-ESR) experiments could be satisfactorily described by the microscopic order macroscopic disorder (MOMD) model in which only the internal dynamics is present. The slowly relaxing local structure (SRLS) model includes fitting parameters for the overall tumbling rates and internal modes. The MOMD model is a limiting case of SRLS model where the overall tumbling is too slow to affect the appearance of the spectrum. On the slower time scale of the 9GHz spectra both the faster internal modes and the slower overall tumbling are important. These studies have provided evidence for the potential of multifrequency ESR to map out the dynamic structure, on a site to site basis, of a macromolecule. The center has recently installed new HFHF-ESR cw spectrometers with superior signal to noise and temperature stability to previous versions, which will allow us to study the dynamic modes of the system with improved sensitivity and throughput capability over a range of frequencies from 9 to 240GHz. The availability of spectra for analysis over a range of frequencies, although a significant computational challenge, will provide detailed insights into the dynamic modes of the system. The implementation of continuously variable coupling to all of our resonators originally developed at 95GHz will be a crucial advance to further improve the sensitivity of our HFHF ESR spectrometers.

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 并且子项目的主要研究者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。 结合高和低 ESR 频率的多频方法可以分解影响通过定点自旋标记 (SDSL) 标记的蛋白质上每个位点标签的复杂动态模式。 在最近一项使用诱变剂对 T4 溶菌酶进行的研究中，自旋标签附着在不同的残基上，我们表明，高场/高频 ESR (HFHF-ESR) 实验可以通过仅存在内部动力学的微观秩序宏观无序 (MOMD) 模型令人满意地描述。 缓慢松弛局部结构 (SRLS) 模型包括整体翻滚速率和内部模式的拟合参数。 MOMD 模型是 SRLS 模型的极限情况，其中整体翻滚太慢而不会影响光谱的外观。 在 9GHz 频谱的较慢时间尺度上，更快的内部模式和更慢的整体翻滚都很重要。 这些研究为多频 ESR 在逐点绘制大分子动态结构方面的潜力提供了证据。 该中心最近安装了新的 HFHF-ESR 连续光谱仪，其信噪比和温度稳定性优于以前的版本，这将使我们能够研究系统的动态模式，在 9 至 240GHz 的频率范围内提高灵敏度和吞吐量能力。 尽管在计算上存在重大挑战，但可用于在一系列频率上进行分析的频谱的可用性将为系统的动态模式提供详细的见解。 对我们最初在 95GHz 开发的所有谐振器实施连续可变耦合将是进一步提高我们的 HFHF ESR 光谱仪灵敏度的关键进步。