Ultra-low-temperature (6 K) static NMR-DNP for metalloproteins, proteins in cells, and materials

超低温（6 K）静态NMR-DNP用于金属蛋白、细胞中的蛋白质和材料 摘要 固态核磁共振（ssNMR）的关键重要性最近被证明，经过近二十年的研究， 经过艰苦的努力，产生了A β 40和A β 42淀粉样蛋白纤维的第一个原子分辨率结构，它们发挥着重要作用。 在阿尔茨海默病（AD）中的重要作用。NMR固有的低灵敏度带来的挑战可能是 通过将样品和电路温度降低到低于100 K，或优选低于35 K来改进-还 称为超低温（Ultra Low Temperature，简称ULT）。将1HNMR与另一种新兴技术相结合， 动态核极化（DNP），显示了巨大的希望，扩大ssNMR的作用，提供 在许多情况下显著的S/N增强。然而，尽管S/N可能从 DNP，也在~90 K下进行，在美国仍然只有少数高场MAS-DNP系统。 因为它们太贵了（3 - 1000万美元）。此外，没有市售的仪器可用。 对于低于90 K的NMR实验，更不用说与DNP结合的NMR实验了。一个巨大的进步 将包括开发一个高模式太赫兹腔，以更有效地将微波传递到样品， 从而能够使用较低功率和较低成本的微波源。ssNMR的一个领域， 使用非旋转（静态）样品将极大地受益于这种商业构建的 双探针，可选择包含DNP。此外，静态探头可以作为MAS版本的原型。 锡永的一个探头。该项目下提出的发展旨在降低DNP的入门级成本 提高了一个数量级以上，同时减少了某些操作挑战。

Ultra-low-temperature (6 K) static NMR-DNP for metalloproteins, proteins in cells, and materials Abstract The critical importance of solid-state NMR (ssNMR) was recently demonstrated by, after nearly two decades of intense efforts, yielding the first atomic-resolution structures of the A40 and A42 amyloid fibrils that play a crucial role in Alzheimer’s Disease (AD). Challenges posed by the inherently low sensitivity of NMR can be improved by reducing the sample and circuit temperature to below 100 K, or preferably below 35 K – also known as Ultra Low Temperature (ULT). Combining ULT NMR with another emerging technique, denoted as dynamic nuclear polarization (DNP), shows enormous promise for expanding the role of ssNMR by providing significant S/N enhancements in many cases. However, despite the huge gain in S/N that is possible from DNP, also performed at ~90 K, there are still only a handful of high-field MAS-DNP systems in the U.S. – pri- marily because they are so expensive ($3-10M). Further, no commercially available instrumentation is availa- ble for NMR experiments below 90 K, let alone ULT experiments combined with DNP. A huge step forward would include the development of a high-mode THz cavity for more efficient microwave delivery to the sample, thus enabling the use of a lower power and lower cost microwave source. An area of ssNMR that employs the use of non-spinning (static) samples would benefit immensely from the availability of such a commercially built ULT probe, with option for inclusion of DNP. Further, the static probe can serve as a prototype for a MAS ver- sion of such a probe. The developments proposed under this project aim to reduce entry level cost into DNP by more than an order of magnitude while reducing certain operational challenges.