CHOLESTANE SPIN LABEL (CSL) STUDIES W/ O TERPHENYL (OTP)

不含三苯基 (OTP) 的胆甾烷旋转标签 (CSL) 研究

• 批准号: 7956585
• 负责人: KEITH A EARLE
• 金额: $ 0.79万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7956585
• 关键词: Biological Models; Cholestanes; Complex; Computer Retrieval of Information on Scientific Projects Database; Frequencies; Funding; Glass; Grant; Institution; Magnetism; Measures; Modeling; Motion; Reporting; Research; Research Personnel; Resolution; Resources; Solubility; Solvents; Source; Spin Labels; Structure; Technology; United States National Institutes of Health; experience; microwave electromagnetic radiation; molecular dynamics; solute

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. One of the main virtues of high-field/high-frequency-ESR (HFHF-ESR) over ESR at conventional microwave frequencies is the excellent orientational resolution that it provides for studies utilizing nitroxide spin labels. As a result, at 250GHz, once motion is discernible in the spectrum, one can study in great detail about which axis (or axes) the motion occurs. We have shown that HFHF-ESR slow-motional spectra are much more sensitive to the details of the molecular dynamics than are those at microwave frequencies. A related important feature of the HFHF-ESR studies is the ability to measure very accurately from (near) rigid limit spectra, the magnetic tensors needed for studies of molecular dynamics. Given the superior orientational resolution of HFHF-ESR, we have developed the slowly relaxing local structure (SRLS) model to explore in a consistent manner the interaction of the solute spin label with the dynamic solvent cage (DSC) and its effects on the molecular dynamics. We have chosen OTP as a convenient model system for exploring the enhanced sensitivity of HFHF-ESR spectra to report on details of the local DSC. Although the SRLS model does describe, in a relatively simple manner, the essential features of the DSC, which had been absent from earlier fitting models, it does require increased computational effort. We are using the experience gained from studying the ESR spectra of a variety of spin labels dissolved in the fragile glass former OTP in projects that will study the more complex dynamics of a variety of bio-molecules at the higher frequencies available to us. In this regard, the CSL spin label is an extremely useful probe, given its ready solubility in the cytosolic leaflet. With the assistance of Dr. Hofbauer, we have recently obtained 2D-COSY results on CSL in model systems that give us confidence in the soundness of this approach.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 在常规微波频率下，高场/高频率-ESR（HFHF-ESR）的主要优点之一是它为利用硝基氧化物自旋标记的研究提供了出色的方向分辨率。结果，在250GHz时，一旦运动在频谱中可见，就可以详细研究运动发生的轴（或轴）。 我们已经表明，与微波频率相比，HFHF-ESR慢速光谱对分子动力学的细节更为敏感。 HFHF-ESR研究的一个相关重要特征是能够从（近）刚性极限光谱（分子动力学研究所需的磁张量）中非常准确地测量的能力。 鉴于HFHF-ESR的优质分辨率，我们开发了缓慢放松的局部结构（SRLS）模型，以一致的方式探索溶质自旋标签与动态溶剂笼（DSC）的相互作用及其对分子动力学的影响。 我们选择了OTP作为便捷的模型系统，用于探索HFHF-ESR光谱的增强灵敏度，以报告本地DSC的详细信息。 尽管SRLS模型确实以相对简单的方式描述了DSC的基本特征，而DSC的基本特征是早期拟合模型所没有的，但它确实需要增加计算工作。 我们正在利用研究溶解在脆弱玻璃前OTP中的各种自旋标签的ESR光谱中获得的经验，这些项目将在我们可用的较高频率上研究各种生物分子的更复杂动力学。 在这方面，CSL自旋标记是一种非常有用的探针，鉴于其在胞质小叶中的现成溶解度。 在Hofbauer博士的协助下，我们最近在模型系统中获得了CSL的2D-COSY结果，这使我们对这种方法的合理性有信心。