Equipment for X-ray Analysis of Biological Macromolecules

生物大分子X射线分析设备

• 批准号: 9419592
• 负责人: Jon Robertus
• 金额: $ 17.58万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-03-15 至 1998-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9419592&HistoricalAwards=false
• 关键词: Equipment; ray; Analysis; Biological; Macromolecules

This proposal requests funds to upgrade facilities for analysis of biological macromolecules, using X-ray diffraction, at the University of Texas. The equipment will be used in the research of two established investigators and two newly appointed assistant professors. It falls into three categories, A. X-ray diffraction, B. high speed computing, and C. molecular graphics. A. The diffraction equipment consists of a high brilliance rotating anode X-ray generator and a state of the art imaging plate (IP) area detector. The detector captures X-rays as metastable centers on a BaFBr:EuX-phosphor, which is read by subsequent laser activation. This type of detector has the spatial resolution to accommodate both single crystal protein diffraction and the low angle scattering patterns generated by the users of the equipment. B. A high speed, dual processor, computer with 4 Gbytes of disk capacity will be used largely for molecular model refinement. This machine will allow timely turnover of simulated annealing refinements using the program XPLOR. It will also be used for sophisticated analysis of low angle scattering patterns. C. A modern molecular graphics station will be acquired. This instrument will augment a heavily used molecular graphics capacity and may be required to replace a failing instrument currently in use. The research interests of the user group are quite varied, involving a number of biologically important systems under study by a range of methodologies. Proteins under study by single crystal analysis include: ribosome inhibiting proteins like ricin, PAP and ebulin; plant and fungal chitinases; the antifungal protein zeamatin; at least four structurally different amino acid decarboxylases including ornithine, arginine and histidine decarboxylases; several invertebrate hemoglobins; multienzyme complexes, like PDC; and the ribosomal RNA binding protein L9. In addition to single crystal studies, the equipment will be used in the low angle scattering ana lysis of polymerizable lipid assemblies. Systematic studies are underway to define the rules governing subassembly in the planes of lipid bilayers. The above projects tend to extend well beyond simply describing the initial X-ray structure. Each protein is refined in a crystallographic sense to the limits of it data in order to produce as accupate a molecular model as possible. Also, the binding of substrate analogs or other ligands is assessed where appropriate. Several of the research groups have vigorous site-directed mutagenesis programs which create a family of proteins whose X-ray analysis is important to describing their structure/function relationships. Finally, structure-based drug design is being developed. The design paradigm requires analysis and energy refinement of numerous intermediate structures. The equipment requested is of great importance to the continuation of established programs and to the expansion of new ones. The X-ray generator and IP detector, together with a cold temperature apparatus, are important for data collection on the many systems under study. Some of these crystal systems have large unit cells and require lengthy time periods or several crystals for complete data collection. Some projects involve a large number of mutant, inhibited, or liganded structures, and in all cases it is desirable to collect as high resolution data as possible. All of these considerations argue for increased data collecting capacity. Furthermore, research projects involving low angle scattering work on bilayer structures cannot be carried out, for technical reasons, without acquisition of the new equipment. The requested computing upgrade will allow modern structural refinement programs, such as XPLOR, to run expeditiously. It will also allow the most modern and powerful data analysis programs for single crystal and low angle scattering analysis to be executed with comparative ease. The need for this system is intensified by the apparent demise of the University managed supercomputer. With over a dozen students and other scientists using the facilities, there is a strain on current molecular graphics equipment. A new unit will allow proper analysis of the mass of structural work being done particularly if one key instrument, currently in place, fails.

该提案要求资金升级德克萨斯大学使用x射线衍射分析生物大分子的设备。该设备将用于两名老研究员和两名新任命的助理教授的研究。它分为三大类，A. x射线衍射，B.高速计算和C.分子图形学。a .衍射设备由一个高亮度旋转阳极x射线发生器和一个最先进的成像板（IP）区域探测器组成。探测器捕获的x射线作为亚稳中心在BaFBr: eux荧光粉，这是由随后的激光激活读取。这种类型的探测器具有空间分辨率，以适应单晶蛋白质衍射和低角度散射模式产生的设备的用户。B.具有4gb磁盘容量的高速双处理器计算机将主要用于分子模型的细化。这台机器将允许使用XPLOR程序及时周转模拟退火精细化。它还将用于低角度散射模式的复杂分析。C.将获得一个现代化的分子图形站。该仪器将增加大量使用的分子制图能力，并可能需要取代目前正在使用的故障仪器。用户群体的研究兴趣各不相同，涉及用一系列方法研究的若干重要的生物学系统。单晶分析研究的蛋白质包括：核糖体抑制蛋白，如蓖麻蛋白、PAP和ebulin；植物和真菌几丁质酶；抗真菌蛋白玉米蛋白；至少四种结构不同的氨基酸脱羧酶，包括鸟氨酸、精氨酸和组氨酸脱羧酶；几种无脊椎动物血红蛋白；多酶复合物，如PDC；核糖体RNA结合蛋白L9。除了单晶研究外，该设备还将用于可聚合脂质组件的低角度散射和裂解。系统的研究正在进行中，以确定在脂质双层平面上控制亚组装的规则。上述项目往往远远超出简单地描述初始x射线结构。每一种蛋白质在晶体学意义上都被细化到它数据的极限，以便产生尽可能准确的分子模型。此外，在适当的地方评估底物类似物或其他配体的结合。几个研究小组有强有力的定点诱变计划，创造了一个蛋白质家族，其x射线分析对描述其结构/功能关系很重要。最后，基于结构的药物设计正在发展。设计范式需要对众多中间结构进行分析和能量优化。所要求的设备对于现有方案的继续和新方案的扩大是非常重要的。x射线发生器和IP探测器，连同一个低温装置，对于正在研究的许多系统的数据收集是重要的。这些晶体系统中的一些有大的单元格，需要很长的时间周期或几个晶体来完成数据收集。一些项目涉及大量的突变、抑制或配位结构，在所有情况下都希望收集尽可能高分辨率的数据。所有这些考虑都支持增加数据收集能力。此外，由于技术原因，如果没有新设备，涉及双层结构低角度散射工作的研究项目就无法进行。所要求的计算升级将允许现代结构优化程序，如XPLOR，快速运行。它还将允许单晶和低角度散射分析的最现代和最强大的数据分析程序相对容易地执行。由于大学管理的超级计算机的明显消亡，对这个系统的需求加剧了。由于有十几名学生和其他科学家使用这些设备，现有的分子图形设备存在压力。一个新的单位将允许对正在进行的大量结构工作进行适当的分析，特别是如果目前到位的一个关键仪器出现故障。