Q-band Upgrade to an X-band Pulsed EPR spectrometer

摘要 34 GHz连续脉冲电子顺磁共振谱仪 （Q波段）是由麻省理工学院化学，哈佛医学院，哈佛的研究人员要求的 化学和布兰代斯生物化学。该仪器的功能包括脉冲ENDOR和 埃尔德。Q波段仪器的主要动机是大大提高了灵敏度， 与我们目前的X波段（9 GHz）光谱仪相比，我们在34 GHz处提供了更高的分辨率。这 提高灵敏度和分辨率将使我们能够解决目前存在的许多问题， 超出了我们的科学范围。该仪器将补充高端X射线晶体学， 核磁共振（NMR）和冷冻电子显微镜（cryoEM）的能力， 波士顿地区使多学科结构生物学和机械生物化学 研究具有重要生物学和医学意义的问题。研究项目 来自六个主要用户组（Griffin、Nocera、Nolan、Pandelia、Raines和Suess）以及来自 另外三个小团体（Betley Keissling和瓦格纳）也包括在提案中。 该工具将促进以下与健康有关的研究： 自由基SAM酶中的活性中间体，参与人体免疫的金属酶， 模拟固氮酶FeMo-辅因子的多核Fe络合物; 2）脉冲EPR/DNP方法 目的是开发在高场下动态标记蛋白质的方法; 3）DEER研究 膜和可溶性蛋白、胶原和多糖的二级结构;。我们 预计进一步的项目针对重要的膜蛋白，例如在神经 疾病和麻醉;病毒和细菌蛋白质在传染病中的重要性将出现 在光谱仪的寿命期间。

Summary. A continuous wave and pulsed electron paramagnetic (EPR) spectrometer operating at 34 GHz (Q-band) is requested by investigators at MIT Chemistry, Harvard Medical School, Harvard Chemistry and Brandeis Biochemistry. The instrument’s capabilities include pulsed ENDOR and ELDOR. The primary motivation for the Q-band instrument is the much improved sensitivity and resolution available at 34 GHz as compared to our current X-band (9 GHz) spectrometer. This improved sensitivity and resolution will permit us to address many problems which at the moment are beyond our scientific reach. The instrument will complement high-end X-ray crystallography, nuclear magnetic resonance (NMR), and cryoelectron microscope (cryoEM) capabilities in the Boston area to enable multidisciplinary structural biology and mechanistic biochemistry investigations of questions that are of great biological and medical importance. Research projects from six major user groups (Griffin, Nocera, Nolan, Pandelia, Raines, and Suess) and those from another three minor groups (Betley Keissling, and Wagner) are included in the proposal. The instrument will advance the following health-related research: 1) ENDOR and ESSEM studies of reactive intermediates in radical SAM enzymes, metalloenzymes involved in human immunity, and polynuclear Fe complexes that mimic the nitrogenase FeMo-cofactor; 2) pulsed EPR/DNP methods aimed at developing methods to dynamically polarize proteins at high fields and 3) DEER studies of membrane and soluble proteins, collagen, and polysaccharide secondary structure;. We anticipate that further projects targeting membrane proteins important for example in neurological disease and anesthesia; and viral and bacterial proteins important in infectious disease will appear during the lifetime of the spectrometer.