Purchase of Bruker Pulse EPT Spectrometer

描述(由申请者提供)：需要资金购买一台Bruker Elexsys 580 EPR光谱仪。这是一台通用性很强的商用EPR仪器，将能够进行连续波操作以及具有ns时间分辨率的广泛脉冲实验。需要能够实现饱和度恢复以及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：PRORS。科比和卡菲索在化学系和教授。Perozo，Tamm和Nakamoto，分子生理学系。该设施也将提供给该大学的其他研究小组。这一用户群目前大量使用弗吉尼亚大学现有的CW EPR功能，然而，目前校园内或附近没有能够执行脉冲EPR测量的仪器。这一组中的大多数用户正在进行的工作涉及到定位自旋标记来确定膜蛋白的结构和动力学。一个小组正在使用顺磁性物种(如氮氧化物)来产生核弛豫增强作用，并确定蛋白质的动力学。与连续波实验相比，脉冲EPR实验能够直接确定电子自旋-晶格驰豫速率和自旋之间的交换。确定自旋之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，并且不需要获取非相互作用的参考光谱。此外，脉冲实验可以消除连续波实验中由于取向各向异性引起的问题。该用户组将使用PULSE EPR提供有关促进跨生物膜运输的蛋白质的结构和结构变化、促进细胞信号系统中的膜附着的蛋白质的结构和机制以及蛋白质介导膜融合的机制的信息。

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.