X-RAY ABSOPTION STUDY ON BACTERIOCHLOROPHYLL ORGANIZATION IN CHLOROSOMES

叶绿体叶绿素组织的X射线吸收研究

• 批准号: 7370647
• 负责人: TEEMU IKONEN
• 金额: $ 0.02万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7370647
• 关键词: RAY; ABSOPTION; STUDY; BACTERIOCHLOROPHYLL; ORGANIZATION

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. Chlorosomes are light harvesting complexes from filamentous and sulphur green photo-synthetic bacteria. The chlorosome is the only photosynthetic antenna complex found in nature in which the chlorophyll molecules are not organized by a protein matrix, but by interactions between the various bacteriochlorophyll (BChl) molecules themselves. It is also the only antenna complex for which structural information is still scarce. One of the active sites guiding the self-assembly of chlorosomes is the central magnesium atom in the BChl porphyrin ring. We aim to elucidate the details of the inter-molecular bonding in chlorosomes by probing the surroundings of the magnesium site with X-ray absorption spectroscopy. The required photon energies range from 1300 eV to 2000 eV and above. Our plan is to compare the BChl bonding in native chlorosomes to a series of polycrystalline chlorophyll samples with known structures. In addition, our simulations show that Mg-coordination numbers and bond lengths to oxygen atoms from neighboring BChl molecules can be obtained from the XANES and EXAFS signals.

该子项目是利用 NIH/NCRR 资助的中心拨款提供的资源的众多研究子项目之一。子项目和研究者 (PI) 可能已从另一个 NIH 来源获得主要资金，因此可以在其他 CRISP 条目中得到体现。列出的机构是中心的机构，不一定是研究者的机构。叶色体是来自丝状和硫绿光合细菌的光捕获复合物。叶绿体是自然界中发现的唯一光合天线复合体，其中叶绿素分子不是由蛋白质基质组织的，而是由各种细菌叶绿素 (BChl) 分子本身之间的相互作用组织的。它也是唯一结构信息仍然匮乏的天线复合体。引导叶绿体自组装的活性位点之一是 BChl 卟啉环中的中心镁原子。我们的目标是通过用 X 射线吸收光谱探测镁位点的周围来阐明叶绿体内分子间键合的细节。所需的光子能量范围为 1300 eV 至 2000 eV 及以上。我们的计划是将天然叶绿体中的 BChl 键合与一系列具有已知结构的多晶叶绿素样品进行比较。此外，我们的模拟表明，可以从 XANES 和 EXAFS 信号中获得邻近 BChl 分子的 Mg 配位数和与氧原子的键长。