FACILITY CHARACTERIZATION FOR ANOMALOUS SOLUTION X-RAY SCATTERING IN STRUCTURAL

结构中异常溶液 X 射线散射的设施表征

• 批准号: 7598332
• 负责人: MARC NIEBUHR
• 金额: $ 1.23万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7598332
• 关键词: Characteristics; Computer Retrieval of Information on Scientific Projects Database; Elements; Equus caballus; Feasibility Studies; Ferritin; Fluorescence; Funding; Grant; Hour; Institution; L-Selenomethionine; Localized; Measurement; Metals; Process; Proteins; Publishing; Reporting; Research; Research Personnel; Resolution; Resources; Solutions; Source; Spleen; System; Technology; United States National Institutes of Health; X-Ray Crystallography; absorption; detector; improved; interest; radius bone structure; research study; structural biology; success

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The significantly improved beam characteristics provided by the SPEAR3 upgrade, in particular improved beam brightness and stability, provide an excellent opportunity for revisiting some of the highly challenging x-ray scattering studies in structural biology. Recent advances in the use of artificially introduced anomalous scatterers, namely SeMet and Au-clusters primarily developed for single crystal diffraction studies, have brought renewed interests in anomalous solution scattering studies, which has had limited success in the past using naturally occurring anomalous scattering elements. As the first feasibility study at SSRL in nearly two decades, we conducted anomalous protein solution scattering experiments on horse spleen ferritin at the Fe K absorption edge (7113 eV). We successfully detected the anomalous scattering effect, reproducing the principal results reported by Stuhrmann (Acta Cryst A36, 996-1001, 1980). Briefly described, we recorded clear deflection in the radius of gyration (Rg) to 37.6 ¿ at the K edge from 36 ¿, consistent with the higher contrast of Fe species which are localized in the periphery of the molecule. This also demonstrates that the energy resolution of our monochromator and the energy stability of ca 0.6 eV over several hours are adequate for anomalous scattering studies. Our result is consistent with the published values of 44 ¿ and 42 ¿. We interpret the difference in Rg values due to a higher level of interparticle interference caused by the higher protein concentration in our experiments. We are encouraged by this result, and plan on studying more challenging protein systems at more dilute metal concentrations. We are in the process of incorporating the Radiant Detector Technology¿s Vortex-EX energy resolving detector (purchased at the end of the last grant year) for absorption edge measurements in fluorescence mode.

该副本是使用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这是调查员的机构。 Spear3升级提供的显着改善的光束特性，特别是改善的梁亮度和稳定性，为重新审视结构生物学中一些高度挑战的X射线散射研究提供了绝佳的机会。人工引入异常散射体的使用最新进展，即SEMET和主要用于单晶衍射研究的AU群集，引起了对异常溶液散射研究的重新兴趣，这些散射研究在过去使用自然出现的异常散射元素在过去的成功有限。作为近二十年来SSRL的首次可行性研究，我们在Fe K受损边缘（7113 eV）的马sleen铁蛋白上进行了异常蛋白溶液散射实验。我们成功地检测到了异常的散射效应，再现了Stuhrmann报告的主要结果（Acta Cryst A36，996-1001，1980）。简而言之，我们记录了回旋半径（RG）的清晰挠度至37.6`在36€的K边缘，与位于分子周围的Fe物种的较高对比相一致。这还表明，我们的单色仪的能量分辨率以及在几个小时内Ca 0.6 eV的能量稳定性足以用于异常散射研究。我们的结果与已发布的44€和42€的值一致。我们解释了由于实验中较高的蛋白质浓度引起的较高颗粒间干扰而导致的RG值差异。我们对此结果感到鼓舞，并计划以更稀释的金属浓度研究更多的挑战蛋白系统。我们正在将辐射探测器技术纳入荧光模式下的抽象边缘测量值。