Single-Complex Spectroscopy of Photosynthetic Systems

光合作用系统的单复合光谱

• 批准号: 9904612
• 负责人: Walter Struve
• 金额: $ 25万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9904612&HistoricalAwards=false
• 关键词: Single; Complex; Spectroscopy; Photosynthetic; Systems

StruveMCB-9904612This project will examine fluorescence excitation spectra of light-harvesting pigment-protein complexes from green bacteria, blue-green bacteria, and higher green plants. Far-field optical techniques with ~ 1 micron spatial resolution will be used to selectively excite and detect chlorophyll and bacteriochlorophyll fluorescence from single complexes at low temperatures. This will greatly simplify the interpretation of their electronic spectra. The latter are ordinarily featureless, smeared by protein inhomogeneities in bulk samples; they become highly structured and analyzable in single-complex spectra. The target systems include Fenna-Matthews-Olson trimers and chlorosomes from green bacteria, photosystem I trimers from cyanobacteria, and photosystem II antenna -reaction center complexes from spinach.Single-molecule spectroscopy (which has been little applied to pigment-protein complexes so far) offers inherently far higher information content than conventional spectroscopy. It can bear new clues regarding the 3-dimensional organization of light-harvesting molecules, the amount and importance of protein disorder, and the strength of the intermolecular interactions underlying their energy transfer role. It can provide novel and decisive evidence for the correct assignment of absorption bands to specific(groups of) molecules identified in protein crystal structures - a key step toward the long-term goal of understanding protein structure-function relationships.

StruveMCB-9904612这个项目将研究来自绿色细菌、蓝绿色细菌和高等绿色植物的捕光色素-蛋白质复合体的荧光激发光谱。空间分辨率为1微米的远场光学技术将被用来在低温下选择性地激发和检测单一络合物中的叶绿素和细菌叶绿素荧光。这将大大简化对它们的电子光谱的解释。后者通常没有特征，被大样本中的蛋白质不均一性所玷污；它们变得高度结构化，可在单一络合光谱中分析。目标系统包括来自绿色细菌的Fenna-Matthews-Olson三聚体和绿体，来自蓝藻的光系统I三聚体，以及来自菠菜的光系统II天线-反应中心复合体。单分子光谱学(到目前为止还很少应用于色素-蛋白质复合体)提供了比传统光谱学更高的信息含量。它可以提供关于捕光分子的三维组织，蛋白质无序的数量和重要性，以及分子间相互作用的强度的新线索，这些都是潜在的能量转移作用。它可以为蛋白质晶体结构中确定的特定(组)分子正确分配吸收带提供新的决定性证据--这是朝着了解蛋白质结构-功能关系的长期目标迈出的关键一步。