当前位置: X-MOL 学术Prog. Nucl. Magn. Reson. Spectrosc. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Quantitative cw Overhauser effect dynamic nuclear polarization for the analysis of local water dynamics
Progress in Nuclear Magnetic Resonance Spectroscopy ( IF 6.1 ) Pub Date : 2013-10-01 , DOI: 10.1016/j.pnmrs.2013.06.001
John M Franck 1 , Anna Pavlova , John A Scott , Songi Han
Affiliation  

Liquid state Overhauser effect Dynamic Nuclear Polarization (ODNP) has experienced a recent resurgence of interest. The ODNP technique described here relies on the double resonance of electron spin resonance (ESR) at the most common, i.e. X-band (∼10GHz), frequency and ¹H nuclear magnetic resonance (NMR) at ∼15 MHz. It requires only a standard continuous wave (cw) ESR spectrometer with an NMR probe inserted or built into an X-band cavity. We focus on reviewing a new and powerful manifestation of ODNP as a high frequency NMR relaxometry tool that probes dipolar cross relaxation between the electron spins and the ¹H nuclear spins at X-band frequencies. This technique selectively measures the translational mobility of water within a volume extending 0.5-1.5 nm outward from a nitroxide radical spin probe that is attached to a targeted site of a macromolecule. It allows one to study the dynamics of water that hydrates or permeates the surface or interior of proteins, polymers, and lipid membrane vesicles. We begin by reviewing the recent advances that have helped develop ODNP into a tool for mapping the dynamic landscape of hydration water with sub-nanometer locality. In order to bind this work coherently together and to place it in the context of the extensive body of research in the field of NMR relaxometry, we then rephrase the analytical model and extend the description of the ODNP-derived NMR signal enhancements. This extended model highlights several aspects of ODNP data analysis, including the importance of considering all possible effects of microwave sample heating, the need to consider the error associated with various relaxation rates, and the unique ability of ODNP to probe the electron-¹H cross-relaxation process, which is uniquely sensitive to fast (tens of ps) dynamical processes. By implementing the relevant corrections in a stepwise fashion, this paper draws a consensus result from previous ODNP procedures and then shows how such data can be further corrected to yield clear and reproducible saturation of the NMR hyperpolarization process. Finally, drawing on these results, we broadly survey the previous ODNP dynamics literature. We find that the vast number of published, empirical hydration dynamics data can be reproducibly classified into regimes of surface, interfacial, vs. buried water dynamics.

中文翻译:

用于分析局部水动力学的定量连续波奥豪塞效应动态核极化

液态奥豪瑟效应动态核极化(ODNP)最近重新引起了人们的兴趣。这里描述的 ODNP 技术依赖于最常见的电子自旋共振 (ESR) 的双共振,即 X 波段 (∼10GHz)、频率和 ∼15 MHz 的 1H 核磁共振 (NMR)。它只需要一个标准连续波 (cw) ESR 波谱仪,并在 X 波段腔中插入或内置 NMR 探头。我们重点回顾 ODNP 作为高频 NMR 弛豫测量工具的一种新的强大表现,可探测 X 波段频率下电子自旋和 1H 核自旋之间的偶极交叉弛豫。该技术选择性地测量从连接到大分子目标位点的硝基氧自由基自旋探针向外延伸 0.5-1.5 nm 的体积内水的平移迁移率。它允许人们研究水合或渗透蛋白质、聚合物和脂质膜囊泡的表面或内部的水的动力学。我们首先回顾了最近的进展,这些进展有助于将 ODNP 开发成一种绘制亚纳米局部水合水动态景观的工具。为了将这项工作连贯地结合在一起,并将其置于 NMR 弛豫测量领域广泛研究的背景下,我们重新表述了分析模型,并扩展了 ODNP 衍生的 NMR 信号增强的描述。该扩展模型强调了 ODNP 数据分析的几个方面,包括考虑微波样品加热所有可能影响的重要性、考虑与各种弛豫率相关的误差的需要,以及 ODNP 探测电子-1H 交叉的独特能力。弛豫过程,对快速(数十皮秒)动态过程特别敏感。通过逐步实施相关校正,本文从以前的 ODNP 程序中得出了一致的结果,然后展示了如何进一步校正这些数据,以产生 NMR 超极化过程的清晰且可重复的饱和度。最后,根据这些结果,我们广泛调查了之前的 ODNP 动态文献。我们发现,大量已发表的经验水合动力学数据可以重复地分为表面、界面和埋藏水动力学状态。
更新日期:2013-10-01
down
wechat
bug