STUDY OF RADIATION DECAY OF PROTEIN CRYSTALS

蛋白质晶体的辐射衰变研究

• 批准号: 8170007
• 负责人: IRIMPAN I MATHEWS
• 金额: $ 2.71万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8170007
• 关键词: Address; Area; Belief; Computer Retrieval of Information on Scientific Projects Database; Data; Data Collection; Data Set; Funding; Gases; Generations; Grant; Institution; Methods; Metric; Photons; Procedures; Proteins; Radiation; Reporting; Research; Research Personnel; Resolution; Resources; Solvents; Source; Synchrotrons; Temperature; Time; United States National Institutes of Health; Writing; infancy; research study

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 high-flux beam lines at third generation synchrotrons produce very high intensity x-radiation. Unfortunately, due to decay of the protein crystals in the high intensity beam, the synchrotrons have to use attenuators to reduce the beam intensity. Therefore, beam lines are not utilizing their full potential for protein diffraction experiments. There have been several attempts to study the mechanisms of protein crystal decay. However, this area of study is still in its infancy. The common belief is that the radiation decay is partly due to the effect of the radicals produced by the interaction of x-ray photons with the protein or solvent atoms in the crystal. Researchers have used various procedures like lowering the data collection temperature, incorporating radical scavengers, etc. to reduce the effect of these radicals. The current study tries to address the radiation decay of protein crystals by employing few selected gases as radical scavengers. This is the first study of this kind and the preliminary results underscore the usefulness of this method. Several protein crystals were used for this study. To reduce the effect of crystal size, this study employed crystals with similar sizes. The data sets were collected at three strong beam lines at SSRL. Continuous decay data were taken for several control crystals and for several crystals exposed to a one of the gases. The primary metric used for calculating the damage accrual rate at a given resolution was the change in I/sigma value reported by MOSFLM over the time range of the data set. 115 GB of diffraction data has been collected and analyzed with scripts written specifically for this purpose. Some of the selected gases showed reduced radiation decay.

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 第三代同步加速器的高通量束线产生非常高强度的x射线。不幸的是，由于高强度光束中蛋白质晶体的衰变，同步加速器不得不使用衰减器来降低光束强度。因此，光束线没有充分利用其在蛋白质衍射实验中的潜力。人们曾多次尝试研究蛋白质晶体衰变的机制。然而，这一领域的研究仍处于初级阶段。人们普遍认为，辐射衰变的部分原因是X射线光子与晶体中的蛋白质或溶剂原子相互作用产生的自由基的影响。研究人员使用了各种程序，如降低数据收集温度，加入自由基清除剂等，以减少这些自由基的影响。目前的研究试图通过使用几种选定的气体作为自由基清除剂来解决蛋白质晶体的辐射衰减问题。这是这类研究的第一次，初步结果强调了这种方法的有效性。本研究使用了几种蛋白质晶体。为了减少晶体尺寸的影响，本研究使用了尺寸相似的晶体。这些数据集是在SSRL的三条强束线上收集的。获得了几个对照晶体和暴露在其中一种气体中的几个晶体的连续衰变数据。在特定分辨率下，用于计算损害累计率的主要指标是农业部报告的I/Sigma值在数据集的时间范围内的变化。已经收集了115 GB的衍射数据，并使用专门为此目的编写的脚本进行了分析。一些选定的气体显示出较低的辐射衰减。