X-RAY EMISSON SPECTROSCOPY OF THE PHOTOSYNTHETIC MN4CA COMPLEX

光合 MN4CA 复合物的 X 射线发射光谱

• 批准号: 8170038
• 负责人: VITTAL YACHANDRA
• 金额: $ 5.29万
• 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/8170038
• 关键词: Address; Aerobic; Algae; Chloride Ion; Chlorides; Complex; Computer Retrieval of Information on Scientific Projects Database; Cyanobacterium; Detection; Development; Electronics; Funding; Future; Grant; Heart; Institution; Life; Ligands; Methods; Natural regeneration; Oxygen; Plants; Process; Raman Spectrum Analysis; Reaction; Research; Research Personnel; Resolution; Resources; Roentgen Rays; Role; Site; Source; Spectrum Analysis; Structure; Techniques; United States National Institutes of Health; Vision; Water; X ray spectroscopy; absorption; catalyst; electronic structure; emission spectroscopy; improved; oxidation; photosystem II; planetary Atmosphere; research study; Address; Aerobic; Algae; Chloride Ion; Chlorides; Complex; Computer Retrieval of Information on Scientific Projects Database; Cyanobacterium; Detection; Development; Electronics; Funding; Future; Grant; Heart; Institution; Life; Ligands; Methods; Natural regeneration; Oxygen; Plants; Process; Raman Spectrum Analysis; Reaction; Research; Research Personnel; Resolution; Resources; Roentgen Rays; Role; Site; Source; Spectrum Analysis; Structure; Techniques; United States National Institutes of Health; Vision; Water; X ray spectroscopy; absorption; catalyst; electronic structure; emission spectroscopy; improved; oxidation; photosystem II; planetary Atmosphere; 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. Oxygen, that supports all aerobic life, is abundant in the atmosphere because of its constant regeneration by photosynthetic water oxidation by green plants, algae and cyanobacteria. This light-requiring reaction is catalyzed by a Mn4Ca cluster associated with photosystem II (PS II). Given the role of PS II in maintaining life on the biosphere and the future visions of a renewable energy economy, it is vital to elucidate the structure and mechanism of the Mn4Ca catalyst, which is sometimes referred to as the ?heart? of the water oxidation process. Although, the electronic and geometric structure of the Mn4Ca water-splitting catalyst has been extensively investigated, the precise structure and mechanism of this catalyst has so far eluded all attempts of determination by x-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) and other spectroscopic techniques. The development of new methods of high resolution absorption and emission x-ray spectroscopy, including x-ray Raman spectroscopy, range-extended EXAFS and site-selective X-ray spectroscopy are critical for providing important new information, that will help in elucidating not only the structure of the complex, but also the mechanism of the photosynthetic water oxidation process. The present proposal builds on the past experiments and addresses some new applications of x-ray emission spectroscopy to the Mn complex in PS II as follows: a) X-ray Raman or RIXS spectroscopy that will address the electronic structure of the Mn complex, b) Kbeta emission and site selective spectroscopy that will selectively probe different Mn sites or different oxidation states in the Mn complex, c) High resolution Mn Kalpha detection of EXAFS that will allow us to collect EXAFS beyond the Fe K-edge thus improving resolution and d) Interatomic Mn Kbeta2,5 spectra that will be a probe for the ligand atoms of Mn, especially to ascertain whether chloride is a ligand of Mn in PS II.

该副本是利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，这不一定是调查员的机构。 氧气支持所有有氧生活的氧气在大气中很丰富，因为它通过光合水的氧化持续再生而被绿色植物，藻类和蓝细菌氧化。与光系统​​II相关的MN4CA簇（PS II）催化了这种灯的反应。鉴于PS II在维持生物圈上的生命以及可再生能源经济的未来愿景中的作用，阐明MN4CA催化剂的结构和机制至关重要，这有时被称为“心脏？水氧化过程。尽管已经广泛研究了MN4CA水分催化剂的电子和几何结构，但该催化剂的精确结构和机制迄今已避免了通过X射线衍射（XRD），扩展的X射线吸收良好结构（EXAFS）和其他光谱技术通过X射线衍射（XRD）确定的所有尝试。高分辨率吸收和发射X射线光谱的新方法的开发，包括X射线拉曼光谱，范围扩展的EXAF和现场选择性X射线光谱对于提供重要的新信息至关重要，这将有助于阐明复合体的结构，还可以阐明光合水的机制。本提案基于过去的实验，并解决了PS II中X射线发射镜头对MN复合体的一些新应用，如下所示：a）X射线拉曼或RIXS光谱，该光谱将解决MN复合物的电子结构，b）KBETA发射和现场选择性谱，可选择性地探究MN MN的不同氧化物，以探测MN的不同氧化物的复合物。 Kalpha检测EXAFS，这将使我们能够收集EXAF，从而超过Fe K边缘，从而改善了分辨率和D）原子间MN KBETA2,5光谱，这将是MN配体原子的探测，尤其是确定氯在PS II中是否是MN的含量。