INCREASING THE DISTANCE RANGE AND RESOLUTION IN PULSED DIPOLAR ESR SPECTROSCOPY

提高脉冲偶极 ESR 光谱的距离范围和分辨率

• 批准号: 8172195
• 负责人: ELKA R GEORGIEVA
• 金额: $ 1.02万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8172195
• 关键词: Binding; Biological; Complex; Computer Retrieval of Information on Scientific Projects Database; Deuterium; Diffusion; Electron Spin Resonance Spectroscopy; Electrons; Evolution; Funding; Grant; Hydrogen; Institution; Lipids; Measurement; Measures; Membrane; Memory; Noise; Phase; Phospholipids; Physiologic pulse; Proteins; Protons; Relaxation; Research; Research Personnel; Resolution; Resources; Signal Transduction; Site; Solutions; Solvents; Source; Spectrum Analysis; Spin Labels; Structure; System; Time; United States National Institutes of Health; cold temperature; improved; interest; mimetics; research study

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. Pulsed dipolar ESR spectroscopy has high capacity for the determination of the structure of biomacromolecules/complexes by performing site-directed distance measurements between spin-labels that are covalently attached to the object of interest. To gain sufficient information for the structure that is studied, several constrains of both short and long distances are needed. However, it is a challenge to measure long inter-spin distances due to the necessity of considerably longer evolution times to be used. This leads to a poor signal-to-noise ratio and not reliable interpretation of the results. The sensitivity of pulsed dipolar ESR experiments can be improved by the increase of the phase memory time Tm. At sufficient low temperatures and concentrations the main relaxation mechanism for the electron spins is related to proton spin diffusion. Therefore, Tm can be extended by appropriate choice of solvent or further by using deuterated solvents as a matrix. The later approach was successfully applied to measure distances up to 7 nm in biological objects in solution. Further complications appear in studies of proteins in membrane-bound state due to the high proton content in the lipids used to prepare the mimetic membranes. Thus to date the longest distances, measured in membrane context, do not exceed 4.5 nm. Herein, for the first time we conducted distances measurements in systems with 70 or high percentage substitution of deuterium for hydrogen in context of matrix, protein molecule and phospholipids.

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。 脉冲偶极ESR光谱法具有高容量来确定生物乳清分子/复合物的结构，通过在共同连接到感兴趣对象的自旋标签之间进行位点定向的距离测量。为了获得所研究的结构的足够信息，需要短距离和长距离的几个约束。但是，由于必须使用相当长的进化时间，测量长时间间隙距离是一个挑战。这导致信噪比差，对结果的解释不是可靠的解释。脉冲偶极ESR实验的灵敏度可以通过相位记忆时间TM的增加来提高。在足够的低温和浓度下，电子旋转的主要松弛机制与质子自旋扩散有关。因此，可以通过适当选择溶剂或将氘化溶剂作为矩阵来扩展TM。后来的方法已成功地用于测量溶液中生物学对象中最高7 nm的距离。由于用于制备模拟膜的脂质中的较高质子含量，因此在膜结合状态下蛋白质的蛋白质研究中出现了进一步的并发症。因此，迄今为止，在膜环境中测量的最长距离不超过4.5 nm。 本文中，我们首次在基质，蛋白质分子和磷脂的背景下，在70或高百分比替代氘代替氢的系统中进行了距离测量。