Resolution and Reconstitution of Photosystem I in Cyanobacteria and Higher Plants; Molecular Biological and Physiochemical Studies

本研究项目旨在研究其结构、功能 光系统I反应中心复合体的结构和功能 蓝藻和绿色植物。 我们解决P700的能力- FA/FB复合物进入P700-FX核心、P700-A1核心和P700-A0 核心，以及我们重建每一个准备的能力， 改变的辅因子和遗传修饰的多肽， 为光系统I的研究提供了新的机会。 的 建议方案是基于解决的能力， 重建光系统I反应中心， 多肽和辅因子，并有五个主要目标： 1)为了确定FA和/或FB在 NADP+的光还原。 2)确认PsaA上FX铁硫簇的配体 和PSAB。 3)确定PsaD、PsaE和PsaF在光系统中的作用 我正常工作。 4)为了求解PsaC、PsaD和PsaD的三维结构， PsaE蛋白。 5)为了测量A1的光谱特性， 重组醌类。 %%% 绿色植物能够利用阳光作为能源 利用光合作用反应中心来驱动 生物体的生长、代谢和繁殖。 两个不同 叶绿体中存在多种反应中心， 绿色植物，每一种都含有叶绿素，蛋白质和金属 将太阳能转化为化学物质所必需的离子 能源 在过去的几年里，我们已经学会了如何消除 来自这些反应中心之一的蛋白质和金属， 我们已经学会了如何重建反应中心 组成部分。 在这份提案中，我们将重建 反应中心使用的蛋白质已经被改变， 现代基因工程技术。 我们将获得这些 通过与几种分子的密切合作， 遗传学家 然后我们将使用复杂的测量技术 以确定单个蛋白质的功能， 光化学能量转换过程。 通过改变一 蛋白质，同时保留其他蛋白质的功能，我们将 能够确定哪种蛋白质提供某种功能， 光合作用的过程。 因此，该提案， 依赖于两个非常强大但截然不同的 技术，遗传学和生物物理学，来解决复杂的 绿色植物光合作用问题。

This research program aims at studying the structure, function and organization of the Photosystem I reaction center complex in cyanobacteria and green plants. Our ability to resolve P700- FA/FB complex into the P700-FX core, the P700-A1 core, and P700-A0 core, and our ability to reconstitute each preparation with altered cofactors and genetically-modified polypeptides, has provided new research opportunities in Photosystem I. The proposed program is based on the ability to resolve and reconstitute the Photosystem I reaction center in terms of polypeptides and cofactors, and has five major objectives: 1) To determine the involvement of FA and/or FB in the photoreduction of NADP+. 2) To confirm the ligands to the FX iron-sulfur cluster on PsaA and PsaB. 3) To determine the roles of PsaD, PsaE and PsaF in Photosystem I function. 4) To solve the 3-dimensional structure of the PsaC, PsaD and PsaE proteins. 5) To measure the spectroscopic properties of A1 with reconstituted quinones. %%% Green plants are able to utilize sunlight as an energy source with the use of photosynthetic reaction centers to power the organism's growth, metabolism, and reproduction. Two different kinds of reaction centers are located in the chloroplasts of green plants, and each contains chlorophyll, proteins, and metals ions necessary for transforming solar energy into chemical energy. In the last several years, we have learned how to remove the proteins and metals from one of these reaction centers, and we have learned how to rebuild the reaction centers from the constituent parts. In this proposal, we will rebuild the reaction centers using proteins that have been altered using techniques of modern genetic engineering. We will obtain these proteins through a close collaboration with several molecular geneticists. We will then use sophisticated measuring techniques to determine the function of the individual proteins in the process of photochemical energy conversion. By altering one protein while retaining the function of the others, we will be able to determine which protein provides a certain function in the process of the photosynthesis. The proposal, therefore, relies on the marriage of two very powerful, but disparate techniques, genetics and biophysics, to solve the complicated problem of green plant photosynthesis.