DEVELOPMENTS FOR SINGLE CRYSTAL XAS INSTRUMENTATION

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。 单晶X射线吸收光谱允许连续测量X射线衍射和X射线吸收数据，使实验人员能够同时获得蛋白质或小分子活性中心的全局结构和原子级局部结构信息。通过安装第二对X射线狭缝以精确定义光束，改进了单晶实验装置。还安装了光束准直器，以最大限度地减少光束散射。测试实验表明，这些加法大大降低了晶片上产生的背景信号。对处于低氧化态的晶体进行了探索性实验，结果表明，液氦冷冻装置不足以维持晶体周围的厌氧气氛，导致晶体缓慢氧化。目前正在制定一种液氮冷却方案来解决这一问题，并将在未来几个月内进行测试。

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. Single crystal x-ray absorption spectroscopy allows for the sequential measurement of x-ray diffraction and x-ray absorption data enabling the experimenter to obtain simultaneous global structure and atomic-level local structure information of a protein or small molecule active site. The single crystal experimental setup has been improved through the installation of a second pair of x-ray slits for precise beam definition. A beam collimator has also been installed to minimize beam scatter. Test experiments show that these additions greatly decrease background signal arising from the crystal mount. Exploratory experiments on crystals in low oxidation states have been carried out, which indicate that a liquid helium cryo-cooling device is insufficient in maintaining an anaerobic atmosphere around the crystal, leading to slow crystal oxidation. A liquid nitrogen cooling protocol is being developed to address this issue and will be tested in the next few months.