IN-SITU UV/VIS SPECTROSCOPY FOR MACROMOLECULAR CRYSTALLOGRAPHY

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者的研究机构。 该项目的目标是能够同时获取X射线衍射数据和紫外/可见光和红外区域的单晶吸收光谱。 在UV（190 - 400 nm）和可见光（400 - 800 nm）区域的吸收光谱的分析提供了关于蛋白质在结晶状态时的电子状态的信息。 在衍射实验期间，分析光谱测量以确认氧化还原状态。未来的实验将包括检测反应中间体的存在或潜在地监测可能通过光解或X射线产生的降解产物。 在BL 11 -1上安装了一台单晶显微分光光度计，用于记录测角仪上晶体的光谱。 光学器件和第二显微镜的定位经过改进以便于使用。 从含有Fe卟啉的晶体收集数据，所述Fe卟啉在5度X射线数据后显示氧化态的降解。 从12个晶体收集完整的数据集，每个晶体提供大约5度的数据。 由此产生的结构的氧化态可以明确地表征。 在这些实验的基础上，目前正在进一步优化仪器设计。

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 goal of this project is to enable the simultaneous acquisition of x-ray diffraction data and single crystal absorption spectra in the UV/Visible and infrared regions. Analysis of the absorption spectrum in the UV (190 - 400 nm) and visible (400 - 800 nm) regions provides information about the electronic state of proteins while in the crystalline state. During diffraction experiments, spectroscopic measurements were analyzed to confirm the redox state. Future experiments will include detecting the presence of reaction intermediates or to potentially monitor degradation products that may be produced either by photolysis or by x-rays. A single crystal microspectrophotometer was set up on BL11-1 to record spectra from crystals on the goniometer. Positioning of the optics and a 2nd microscope were refined for ease of use. Data were collected from crystals containing an Fe porphyrin that showed degradation of the oxidation state after 5 degrees of x-ray data. A complete data set was collected from 12 crystals each providing approximately 5 degrees of data. The resulting structure¿s oxidation state could be unambiguously characterized. Based on these experiments, the instrument design is now being optimized further.