Purchase of Bruker Pulse EPT Spectrometer

描述（由申请人提供）：申请资金用于购买Bruker Elexsys 580 EPR光谱仪。这是一个高度通用的商业EPR机，将能够既CW操作，以及广泛的脉冲实验与ns的时间分辨率。要求能够进行饱和恢复和ELDOR实验的选项。这将是一个多用户仪器，将由化学系安置和维护。主要用户组将由弗吉尼亚大学的五个研究小组组成：化学系的布莱恩特和卡菲索教授和化学系的卡菲索教授。分子生理学系的Perozo，Tamm和Nakamoto。该设施也将提供给大学的其他研究小组。该用户组目前大量使用弗吉尼亚大学现有的CW EPR能力，然而，目前校园内或附近没有能够进行脉冲EPR测量的仪器。这个小组的大多数用户正在进行的工作涉及定点自旋标记，以确定膜蛋白的结构和动力学。一组是使用顺磁性物质（如氮氧化物）来产生核弛豫增强和确定蛋白质的动力学。与CW实验相比，脉冲EPR实验能够直接确定电子自旋-晶格弛豫速率和自旋之间的交换。确定自旋间偶极耦合和估计自旋间距离的方法可以使用脉冲方法扩展到更长的距离，并且不需要采集非相互作用的参考光谱。此外，脉冲实验可以消除由于取向各向异性在连续波实验中的问题。该用户组将使用脉冲EPR提供有关蛋白质的结构和结构变化的信息，这些蛋白质有助于跨生物膜的运输，有助于细胞信号系统中膜附着的蛋白质的结构和机制以及蛋白质介导的膜融合机制。

DESCRIPTION (provided by applicant): Funds are requested to purchase a Bruker Elexsys 580 EPR spectrometer. This is a highly versatile commercial EPR machine that will be capable of both CW operation as well as a broad range of pulse experiments with ns time resolution. Options are requested that will enable saturation recovery as well as ELDOR experiments. This will be a multiuser instrument that will be housed and maintained by the Department of Chemistry. The primary user group will consist of five research groups at the University of Virginia: Profs. Bryant and Cafiso in the Department of Chemistry and Profs. Perozo, Tamm and Nakamoto in the Department of Molecular Physiology. The facility will also be available to other research groups at the University. This user group presently makes heavy use of the existing CW EPR capabilities at the University of Virginia, however, there are presently no instruments on campus or nearby that are capable of performing pulse EPR measurements. The work being carried out by most users in this group involves site-directed spin labeling to determine membrane protein structure and dynamics. One group is using paramagnetic species (such as nitroxides) to produce nuclear relaxation enhancements and determine dynamics in proteins. Compared to CW experiments, pulse EPR experiments enable a direct determination of electron spin-lattice relaxation rates and exchange between between spins. Methods to determine dipolar coupling between spins and estimate interspin distances can be extendent to much longer distances using pulse methods and do not require the acquisition of non-interacting reference spectra. In addition, the pulse experiment can eliminate problems due to orientational anisotropy in the CW experiment. This is user group will use pulse EPR to provide information on the structures and structural changes in proteins that facilitate transport across biological membranes, the structures and mechanisms of proteins that facilitate membrane attachment in cell signaling systems and the mechanisms of protein-mediated membrane fusion.