A Resonator for Pulsed ODNP Spectroscopy to Study Surface Hydration Dynamics

项目总结/摘要 建议的研究重点是发展一个交钥匙谐振器的液体状态奥弗豪泽 动态核极化（ODNP）光谱学研究水的特定位置平移动力学 位于生物大分子如膜蛋白的界面处的分子。这将使研究人员 为了容易地在现有技术的市售X波段cw/脉冲 电子顺磁共振（EPR）光谱仪或使用台式ODNP光谱仪。 近年来，DNP已被证明是一种强大的方法，以增加核磁共振实验中的信号强度 在世界各地的实验室中，在使DNP适用于固体和溶液方面取得了实质性进展， 核磁共振谱。这一进展引发了对ODNP光谱学的新兴趣。尽管方法 自20世纪60年代以来，它已被成功地应用于研究位点特异性翻译 水的动力学位于大的生物大分子如膜蛋白的界面。ODNP可以 绘制出膜蛋白和脂质膜的局部和特定位点的水合动力学景观 并且可以提供关于蛋白质结构和动力学的关键信息。 ODNP光谱学中的主要挑战之一是微波诱导样品加热。在阶段 在本项目中，我们成功地设计、制作并表征了一种新型的ODNP谐振器原型。这 SBIR第二阶段的应用将确保原型可以变成客户产品。证明 通过原型，谐振器将具有比常规谐振器高得多的微波转换因子。 矩形或圆形EPR腔。此外，低Q谐振结构将允许脉冲ODNP 通过降低饱和所需的平均功率来进一步最小化微波诱导加热的实验 EPR过渡。 这项技术的成功开发将为研究人员提供仪器 使他们能够将ODNP光谱学纳入其研究程序，而无需麻烦地排除故障 自制设备这将极大地推广该方法，并对许多由政府资助的项目产生很大的兴趣。 美国国立卫生研究院

Project Summary / Abstract The proposed research focuses on the development of a turn-key resonator for liquid-state Overhauser Dynamic Nuclear Polarization (ODNP) spectroscopy to study the site-specific translational dynamics of water molecules located at the interface of bio-macromolecules such as membrane proteins. It will allow researchers to readily perform ODNP experiments in either a state-of-the-art commercially available X-band cw/pulsed electron paramagnetic resonance (EPR) spectrometer or using a benchtop ODNP spectrometer. In recent years, DNP has proven to be a robust method to increase signal intensities in NMR experiments in laboratories around the world and substantial progress has been made in adapting DNP for solid- and solution- state NMR spectroscopy. This progress has sparked a new interest in ODNP spectroscopy. Although the method is known since the 1960s it has just recently been applied successfully to study the site-specific translational dynamics of water located at the interface of large bio-macromolecules such as membrane proteins. ODNP can map out the local and site-specific hydration dynamics landscape of membrane proteins and lipid membranes and can provide critical information about the protein structure and dynamics. One of the major challenges in ODNP spectroscopy is microwave induced sample heating. During Phase I of this project, we successfully designed, fabricated and characterized a novel prototype ODNP resonator. This SBIR Phase II application will assure that the prototype can be turned into a customer product. As demonstrated by the prototype, the resonator will have a much higher microwave conversion factor compared to conventional rectangular or circular EPR cavities. In addition, the low Q resonance structure will allow pulsed ODNP experiments to further minimize microwave induced heating by reducing the average power required to saturate the EPR transitions. The successful development of this technology will provide researchers access to instrumentation allowing them to incorporate ODNP spectroscopy in their research routine without the hassle of troubleshooting home-built equipment. This will greatly proliferate the method and is of large interest to many projects funded by the U.S. National Institutes of Health.