Mechanism and Macromolecular Organization in Photosynthetic Reaction Centers

光合反应中心的机理和大分子组织

• 批准号: 0416623
• 负责人: Steven Boxer
• 金额: $ 92.48万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0416623&HistoricalAwards=false
• 关键词: Mechanism; Macromolecular; Organization; Photosynthetic; Reaction

AbstractMCB 0416623The objective of this research is to understand the mechanisms of charge separation and recombination in photosynthetic reaction centers (RCs) and the higher-order organization of photosynthetic membranes. Towards understanding electron transfer mechanism, several areas are described: (i) application of newly developed instrumentation for measuring Stark effects in the IR and theory for analyzing intervalence band Stark effects associated with the oxidized special pair; (ii) determination of the parameters that control alternative electron transfer pathways using a newly-developed experimental method, resonance Stark spectroscopy; (iii) application of the resonance Stark method to other pathways created by engineering the RC; (iv) measurement of electric field effects on the populations of charge-separated species in photosystem II RCs, in particular the role of carotenoid cations; and (v) development and application of RC strains in which all native cysteine residues are deleted and new cysteines are inserted as site-specific targets for different types of labels. Towards understanding photosynthetic membrane organization and assembly several areas are described: (i) characterization of the lateral mobility and assembly of antenna protein complexes in supported membranes; and (ii) imaging of components of the photosynthetic membrane in supported lipid bilayers by atomic force microscopy and a novel type of secondary ion mass spectrometry with high lateral resolution. This research uses photosynthetic proteins in supported membranes both as a tool to advance imaging and structural methods and to determine the long-range organization of this important membrane-associated assembly.By integrating this range of approaches, the basic understanding of the mechanism of the initial electron transfer and the related phenomenon of unidirectional electron transfer can be advanced and brought into the larger context of structure-function relationships in complex biological assemblies. Research in the photosynthesis area addresses the general problem of the mechanisms by which the organized environment in proteins modulates the properties of bound prosthetic groups and particular amino acid functional groups with extraordinary functional consequences. An important part of this work involves the development of new experimental and theoretical methods that can have a broad impact in other areas of science and technology. Nearly every spectroscopic, structural, and theoretical method has been applied to some aspect of RC and photosynthetic membrane function. In many cases this was the first example of new physical approaches applied to a biological problem, often leading to significant improvements in the physical and theoretical methods, and these concepts and methods are now used in many other fields. This general area of research has also been a tremendous source of training for undergraduates, graduate students and postdoctoral fellows, often serving as a bridge between the physical sciences and biology. Viewed in broadest terms, concepts and results from photosynthesis research have impacted solar energy research and the emerging area of molecular electronics.

摘要MCB 0416623本研究的目的是了解光合反应中心（RC）中电荷分离和重组的机制以及光合膜的高阶组织。 为了理解电子转移机制，描述了几个领域：（i）应用新开发的仪器来测量红外斯塔克效应，以及分析与氧化特殊对相关的间隔带斯塔克效应的理论； (ii) 使用新开发的实验方法——共振斯塔克光谱法，确定控制替代电子转移途径的参数； (iii) 将共振斯塔克方法应用于通过设计 RC 创建的其他路径； (iv) 测量电场对光系统 II RC 中电荷分离物种群体的影响，特别是类胡萝卜素阳离子的作用； (v) RC菌株的开发和应用，其中所有天然半胱氨酸残基均被删除，并插入新的半胱氨酸作为不同类型标记的位点特异性靶标。 为了理解光合膜的组织和组装，描述了几个领域：（i）支撑膜中天线蛋白复合物的横向移动性和组装的表征； (ii) 通过原子力显微镜和具有高横向分辨率的新型二次离子质谱法对支持的脂质双层中的光合膜成分进行成像。 这项研究使用支持膜中的光合蛋白作为工具来推进成像和结构方法，并确定这种重要的膜相关组装的远程组织。通过整合这一系列方法，可以推进对初始电子转移机制和单向电子转移相关现象的基本理解，并将其带入复杂生物组装中结构功能关系的更大背景中。 光合作用领域的研究解决了蛋白质中的组织环境调节结合辅基和特定氨基酸官能团的特性的机制的一般问题，从而产生非凡的功能结果。 这项工作的一个重要部分涉及开发新的实验和理论方法，这些方法可以对其他科学技术领域产生广泛的影响。 几乎所有光谱、结构和理论方法都已应用于 RC 和光合膜功能的某些方面。 在许多情况下，这是应用于生物学问题的新物理方法的第一个例子，通常会导致物理和理论方法的显着改进，并且这些概念和方法现在被用于许多其他领域。 这一一般研究领域也是本科生、研究生和博士后培训的巨大来源，通常充当物理科学和生物学之间的桥梁。 从最广泛的角度来看，光合作用研究的概念和结果影响了太阳能研究和分子电子学的新兴领域。