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.

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 脉冲偶极ESR光谱通过在共价连接到目标对象上的自旋标记之间进行定点距离测量，具有确定生物大分子/络合物结构的高能力。为了为所研究的结构获得足够的信息，需要几个短距离和长距离的约束。然而，由于需要使用相当长的演化时间，因此测量长自旋间距离是一个挑战。这导致了较差的信噪比和对结果的不可靠解释。增加相记忆时间Tm可以提高脉冲偶极ESR实验的灵敏度。在足够低的温度和浓度下，电子自旋的主要驰豫机制与质子自旋扩散有关。因此，Tm可以通过选择适当的溶剂或进一步使用氢化溶剂作为基质来扩展。后一种方法被成功地应用于测量溶液中生物物体的距离，最大距离可达7 nm。由于用于制备模拟膜的脂类中的质子含量很高，对膜结合状态的蛋白质的研究出现了更多的复杂情况。因此，到目前为止，在膜环境中测量的最长距离不超过4.5 nm。 在这里，我们第一次在基质、蛋白质分子和磷脂的背景下，用70%或更高比例的氢取代氢的体系中进行了距离测量。