PICOSECOND TIME-RESOLVED LAUE CRYSTALLOGRAPHY

皮秒时间分辨劳厄晶体学

• 批准号: 8363673
• 负责人: Philip Anfinrud
• 金额: $ 5.47万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8363673
• 关键词: Active Sites; Address; Allosteric Regulation; Biological Models; Biophysical Process; Crystallography; Data; Data Quality; Event; Evolution; Funding; Grant; Heme; Hemeproteins; Hemoglobin; Investigation; Lasers; Ligand Binding; Ligands; Mediating; Myoglobin; National Center for Research Resources; Pathway interactions; Physiologic pulse; Principal Investigator; Process; Proteins; Research; Research Infrastructure; Resolution; Resources; Roentgen Rays; Role; Source; Structure; Synchrotrons; System; Techniques; Time; Training; United States National Institutes of Health; cost; migration; photolysis; protein structure; quantum; structural biology

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We aim to employ the technique of picosecond time-resolved Laue crystallography to study biophysical processes in proteins. Specifically we will use intense short-duration laser pulses to trigger a structural change in a protein crystal and will probe its structural evolution with single X-ray pulses isolated from the synchrotron pulse train using a sequence of X-ray shutters. By acquiring diffraction data at a well-defined instant in time after laser photolysis we can construct a snapshot of the proteins structure with time resolution limited only by the duration of the X-ray pulse which is of the order of 100 ps. We aim to address numerous biophysical questions including the functional role of highly conserved residues in proteins pathways for ligand migration to and from the proteins active site and the correlated structural changes that mediate or control allosteric regulation. To obtain the highest quality data possible we will focus initially on protein systems whose structural changes are reversible. Ligand-binding heme proteins including myoglobin and hemoglobin are ideal model systems for these biophysical investigations. When CO is used as a surrogate for O2 the ligand can be photodissociated from the heme with high quantum efficiency thereby triggering a sequence of events that can be studies structurally. Because the dissociated ligands rebind to the heme bimolecularly on the ms time scale the structure returns to its starting state and the process can be repeated thousands of times. Thus these model systems are ideal for pursuing these biophysical studies.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的主要研究者可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 我们的目标是采用皮秒时间分辨劳厄晶体学技术来研究蛋白质的生物物理过程。具体来说，我们将使用强烈的短时激光脉冲来触发蛋白质晶体的结构变化，并使用一系列 X 射线快门从同步加速器脉冲串中分离出单个 X 射线脉冲来探测其结构演化。通过在激光光解后的明确时刻采集衍射数据，我们可以构建蛋白质结构的快照，其时间分辨率仅受 X 射线脉冲持续时间（约为 100 ps）的限制。我们的目标是解决许多生物物理问题，包括高度保守的残基在配体进出蛋白质活性位点的蛋白质途径中的功能作用，以及介导或控制变构调节的相关结构变化。为了获得尽可能最高质量的数据，我们将首先关注结构变化可逆的蛋白质系统。包括肌红蛋白和血红蛋白在内的配体结合血红素蛋白是这些生物物理研究的理想模型系统。当 CO 用作 O2 的替代物时，配体可以以高量子效率从血红素光解离，从而触发一系列可以进行结构研究的事件。由于解离的配体在毫秒时间尺度上以双分子方式重新结合到血红素上，因此结构返回到其起始状态，并且该过程可以重复数千次。因此，这些模型系统是进行这些生物物理研究的理想选择。