In-house Small Angle X-Ray Scattering Instrument

 描述(申请人提供)：X射线结晶学和小角X射线散射(SAXS)是研究生物组装和大分子构象变化的强大方法，为高分辨率X射线结晶学和核磁共振提供补充信息。约翰霍普金斯大学在医学院、公共卫生学院和艺术与科学学院有一个由NIH资助的大型研究小组(16个PI)，他们利用SAXS和X射线结晶学来研究NIH任务的一系列核心问题。所要求的内部SAXS系统将有利于使用SAXS的正在进行的项目，同时为研究涉及大分子和络合物的系统打开大门，这些系统随着时间的推移变质和聚集，因此无法运往同步加速器光束线进行SAXS数据收集。所要求的系统利用医学院现有的高亮度发生器，以获得质量最佳的内部SAXS数据。为了保持内部单晶X射线衍射数据采集的高吞吐量，由于我们计划使用两个SAXS发生器端口中的一个，我们还要求使用Pilatus像素阵列探测器来取代目前安装在两个端口上的现有像板和CCD探测器。除了缩短数据收集时间外，Pilatus探测器还提供了额外的好处，即能够筛选较小的晶体并收集更高分辨率的数据集，以进行结构确定工作。所有要求的设备都将被纳入X射线衍射设施，该设施作为核心设施已有20多年，配备了一名经验丰富的博士级结晶学家。该大学对这一设施及其升级作出了大量的财政承诺，包括为X光实验室经理提供全额工资支持、准备好的实验室空间、配套资金，并保证提供持续的财政支持，以支付服务合同和维修费用。该设备将对包括癌症生物学、DNA复制、核糖体组装、细胞内信号、转录调控、基因组完整性、神经功能和多药耐药性在内的广泛领域产生直接和持久的影响。

 DESCRIPTION (provided by applicant): X-ray crystallography and small-angle x-ray scattering (SAXS) are powerful methods for studying biological assemblies and conformational changes in macromolecules that provide information complementary to high-resolution X-ray crystallography and NMR. The Johns Hopkins University has a large group (16 PIs) of NIH-funded investigators in the Schools of Medicine, Public Health, and Arts and Sciences that utilize SAXS and X-ray crystallography to study a range of problems central to the NIH mission. The requested in-house SAXS system will benefit ongoing projects that utilize SAXS while opening the door to studying systems involving macromolecules and complexes that deteriorate and aggregate over time and thus do not survive shipping to synchrotron beamlines for SAXS data collection. The system requested takes advantage of an existing high-brilliance generator housed at the School of Medicine to obtain in-house SAXS data of optimal quality. To maintain high throughput for in-house single- crystal X-ray diffraction data collection, and since we plan t utilize one of two generator ports for SAXS, we also are requesting a Pilatus pixel-array detector to replace the existing image- plate and CCD detectors currently mounted on both ports. In addition to shortening data collection times, a Pilatus detector offers the added benefit of enabling screening of smaller crystals and collecting higher resolution data sets for structure determination efforts. All of the requested equipment will be incorporated into an X-ray diffraction facility that has served as a core facility for over two decades and is staffed by an experienced PhD-level crystallographer. The University has made a substantial financial commitment to this facility and its upgrade, including providing full salary support for the X-ray lab manager, prepared laboratory space, matching funds, and a guarantee of ongoing financial support to cover service contracts and repairs. The equipment will have an immediate and lasting impact on a broad range of areas including cancer biology, DNA replication, ribosome assembly, intracellular signaling, transcriptional regulation, genomic integrity, neuronal function and multidrug resistance.