Upgrade of In-house X-ray Diffraction Equipment

描述(申请人提供)：约翰霍普金斯大学医学院生物物理和生物物理化学系的三个小组使用X射线衍射作为主要研究工具(Amzel，氧化还原酶机制，磷酸转移反应和大分子识别；Leahy，信号转导；Wolberger，基因表达调控)，并且每个小组都与霍普金斯大学的多个小组以及外部机构合作。在过去的几年里，霍普金斯大学药理学系的两个小组(Cole，信号转导和基因表达的化学方法；Stiver，核酸新陈代谢)已经开始使用衍射方法作为他们研究的重要组成部分。这些努力最初是与霍普金斯大学和其他地方的结构生物学家合作，但正在扩大，因此X射线结构测定正在成为他们独立研究工作的一个组成部分。JHUSOM目前的X射线衍射设施已被严重超额认购，我们建议利用内部X射线发生器最近令人印象深刻的进展来提高该设施的容量和能力。具体地说，我们建议购买一台Rigaku 007HF高通量X射线发生器，配备两套VariMax高频光学元件，007HF发生器上的每个端口各一套。我们还建议购买一个R轴IV++图像板探测器，以取代过时的和没有支持的R轴II探测器。现有的R轴IV探测器和两个X-Stream冷冻冷却系统将与R轴IV++一起转移到新的发电机，以创建两个用于大分子结晶学的高通量X射线站。根据测试晶体比较和公布的规格，我们预计新的发电机和光学元件将导致平均数据收集时间减少10倍，并大幅提高项目吞吐量。由于新装置(直径70 5m)比现有装置(直径300 5m)产生的束流尺寸更小，X射线束强度更高，因此新装置将特别有利于从小晶体采集数据，而小晶体是目前实验的主要部分。通过提高生产能力和扩大可获得有用衍射数据的项目范围，升级后的设施将显著增强由NIH资助的广泛的健康相关项目，这些项目涉及信号、基因表达、酶机制和药物设计。

DESCRIPTION (provided by applicant): Three groups in the Department of Biophysics & Biophysical Chemistry at the Johns Hopkins University School of Medicine (JHUSOM) use X-ray diffraction as a primary research tool (Amzel, mechanism of oxidoreductases, phosphoryl transfer reactions, and macromolecular recognition; Leahy, signal transduction; Wolberger, regulation of gene expression), and each of these groups collaborates with multiple groups at Hopkins as well as outside institutions. In the past several years two groups in the Department of Pharmacology at Hopkins (Cole, chemical approaches to signal transduction and gene expression; Stivers, nucleic acid metabolism) have started to use diffraction methods as a significant component of their research. These efforts began as collaborations with structural biologists at Hopkins and elsewhere but are expanding so that X-ray structure determinations are becoming a component of their independent research efforts. The current X-ray diffraction facilities at JHUSOM are heavily oversubscribed, and we propose to take advantage of recent and impressive advances in in-house X-ray generators to increase the capacity and capabilities of this facility. Specifically, we propose to acquire a Rigaku 007HF high-flux X-ray generator equipped with two sets of VariMax HF optics, one for each port on the 007HF generator. We also propose to acquire an R-axis IV++ Image Plate detector to replace an outmoded and unsupported R-axis II detector. An existing R-axis IV detector and two X-stream cryo-cooling systems will be transferred to the new generator along with the R-axis IV++ to create two high-flux X-ray stations for macromolecular crystallography. Based on test crystal comparisons and published specifications, we expect the new generator and optics to result in a 10-fold decrease in average data collection times and a substantial increase in project throughput. Owing to the decreased beam size produced by the new generator (70 5M diameter) vs. the existing equipment (300 5M diameter) and increased X-ray beam intensity, the new setup will be especially advantageous for data collection from small crystals, which make up the majority of current experiments. By increasing throughput and expanding the range of projects for which usable diffraction data can be obtained, the upgraded facility will significantly enhance a broad range of NIH-funded, health-related projects with implications for signaling, gene expression, enzyme mechanism, and drug design.