Acquisition of Q-band Pulsed EPR Capability

描述（由申请人提供）：本申请旨在将我们目前的布鲁克X波段E580脉冲光谱仪升级到Q波段，该光谱仪能够在低温下运行DEER（双电子-电子共振）、DQC（双量子相干）和ENDOR（电子核双共振）实验。当前仪器和升级仪器的主要用途是定量生物医学相关蛋白质上或内的顺磁探针之间的距离测量。从X波段（9 GHz）DEER升级到Q波段（35 GHz）DEER的主要优点是灵敏度提高了10倍以上，距离数据的质量总体上更高。分辨率、准确性、识别、信号强度和更长距离的收集方面的改进将对一系列生物项目产生相当大的好处。脉冲Q波段相对于X波段的其他优点包括更小的样品体积、更低的总体样品浓度要求以及显著减少的数据收集时间。脉冲Q波段ENDOR还提供了超过X波段ENDOR的技术和基本优势。Q波段谐振器允许对于给定的供应功率显著更高的射频（RF）场，这通常是ENDOR灵敏度的限制因素，并且微波场在Q波段增加;这些允许研究不适合脉冲X波段或连续波ENDOR的快速弛豫系统。此外，14 N和1H ENDOR共振通常在X波段重叠，但很容易在Q波段分配。其中每一个都是生物学研究项目的显着优势，加上数据准确性的显著提高，将对当前和未来的可溶性和膜蛋白和蛋白质复合物的结构生物学研究产生重大影响。高于Q波段的频率对所提出的实验几乎没有额外的好处，因此这种升级要求是为了长期使用脉冲EPR光谱的最佳仪器。这种类型的国家的最先进的Q波段脉冲EPR仪器是缺乏不仅在威斯康星州的医学院，但在整个威斯康星州的状态。确定了五个主要用户，他们将测量蛋白质和蛋白质复合物内的长距离。此外，还确定了许多小用户，每个用户都需要该区域没有的先进脉冲仪器。具体而言，从所要求的升级中受益的研究将有助于更好地了解癫痫、心律失常、神经系统疾病和癌症等疾病过程的生理学，并有助于开发新的抗生素和癌症治疗剂。一旦初步提出的项目取得明显成功，预计将发现更多的机会，开辟跨学科科学的进一步途径。这种升级的仪器能力将立即显着提高本提案中概述的项目的生产力，并改善周围社区的研究环境。

DESCRIPTION (provided by applicant): This application is for an upgrade to Q-band for our current Bruker X-band E580 pulse spectrometer capable of running DEER (double electron-electron resonance), DQC (double quantum coherence), and ENDOR (electron nuclear double resonance) experiments at cryogenic temperatures. The primary use of both the current and upgraded instrument will be to quantitate distance measurements between paramagnetic probes on or within biomedically relevant proteins. The major advantages of upgrading to Q-band (35 GHz) DEER from X-band (9 GHz) DEER are a >10-fold increase in sensitivity and overall higher quality distance data. The improvement in resolution, accuracy, identification, signal intensity and the collection of longer distances will be of considerable benefit to an array of biological projects. Additional advantages of pulsed Q- band over X-band include smaller sample volumes, lower overall sample concentration requirements, and significantly decreased data collection times. Pulsed Q-band ENDOR also provides technological and fundamental benefits over X-band ENDOR. The Q-band resonator allows for significantly higher radio frequency (RF) fields for a given supplied power, which is often the limiting factor in ENDOR sensitivity, and the microwave field is increased at Q-band; these allow for the study of fast-relaxing systems that are not amenable to pulsed X-band or continuous-wave ENDOR. In addition, 14N and 1H ENDOR resonances typically overlap at X-band, yet are readily assigned at Q-band. Each one of these is a remarkable advantage to biological research projects and coupled with the considerable improvement in data accuracy will have a substantial impact on current and future structural biology studies of soluble and membrane proteins and protein complexes. Frequencies higher than Q-band provide little additional benefit to the proposed experiments, thus this upgrade request is for the optimum instrument for long-term pulse EPR spectroscopy use. This type of state-of-the-art Q-band pulsed EPR instrumentation is lacking not only at the Medical College of Wisconsin but in entire the state of Wisconsin. Five major users are identified who will measure long-range distances within proteins and protein complexes. In addition, numerous minor users are identified, each with a need for advanced pulse instrumentation not available in the region. Specifically, the research benefiting from the requested upgrade will contribute to a better understanding of the physiology of disease processes such as epilepsy, arrhythmia, neurological disorders, and cancer, and to the development of novel antibiotics and cancer therapeutic agents. Additional opportunities are expected to be uncovered once the success of the initially proposed projects is evident, opening up further avenues of interdisciplinary science. This upgraded instrumentation capability will immediately and significantly advance the productivity of the projects outlined in this proposal as well as enhance the research environment for the surrounding community.