Molecular basis of FtsH function in the cyanobacterium Synechocystis PCC 6803

蓝藻集胞藻 PCC 6803 中 FtsH 功能的分子基础

• 批准号: BB/F020554/1
• 负责人: Peter Nixon
• 金额: $ 41.39万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FF020554%2F1
• 关键词: Molecular; basis; FtsH; function; cyanobacterium

Cyanobacteria are a diverse group of bacteria that have the ability to carry out plant-like photosynthesis, using solar energy to drive the fixation of carbon dioxide into organic matter and the liberation of oxygen from water. They are found in aquatic environments and make an important contribution to global oxygenic photosynthesis. Their photosynthetic activity is therefore crucial to determining levels of carbon dioxide, a greenhouse gas, in the atmosphere. Cyanobacteria are also closely related to the chloroplasts found in plants and many of the biochemical processes are conserved. Consequently cyanobacteria have been widely used as models to study related processes in chloroplasts, such as how the protein components involved in photosynthesis work. In particular the cyanobacterium Synechocystis 6803 is a widely used experimental system because of the ease of doing genetic engineering experiments in this organism. Recently Peter Nixon and colleagues identified a cyanobacterial protease, termed FtsH2, which was involved in the repair of the oxygen-evolving Photosystem II complex following light damage. Homologues of FtsH2 are also involved in the same process in chloroplasts. Subsequently FtsH2 has been shown to be involved in the successful acclimation of Synechocystis 6803 to a number of other environmental stresses including heat, high salt and reduced availability of inorganic carbon. FtsH2 is therefore an important factor controlling a number of different physiological processes vital for survival of the cyanobacterium. In background work to this proposal we have developed the experimental tools to conduct important fundamental studies on this class of FtsH protease. We have developed techniques to purify the FtsH2 protease and have shown that it forms a complex with the related FtsH3 protease. By using electron microscopy we could show for the first time that this FtsH2/FtsH3 complex is made of six subunits. In this application we describe a series of experiments to assess the structure and function of FtsH2 and the other three members of the FtsH protease family found in Synechocystis 6803. We propose to identify the location of each of the FtsH subunits in the cell, determine the number and composition of the different types of FtsH complex in the cell, identify potential targets for each of the FtsH proteases and determine if the physiological effects displayed by the FtsH2 mutants is as a result of the proteolytic activity of the FtsH complex or the ability of FtsH complexes to help pull or refold cellular targets. Beside improving our understanding of how cyanobacteria respond to various environmental stresses, our results will also be of special significance to plant scientists who are trying to understand the role of FtsH in the chloroplast. Ultimately work on the FtsH proteases might allow the generation of photosynthetic organisms, such as crop plants, that are able to grow more productively under a range of environmental conditions including high light stress.

蓝藻是一类多样化的细菌，它们能够进行类似植物的光合作用，利用太阳能驱动将二氧化碳固定为有机物并从水中释放氧气。它们存在于水生环境中，对全球含氧光合作用做出了重要贡献。因此，它们的光合作用对于确定大气中二氧化碳（一种温室气体）的水平至关重要。蓝细菌还与植物中发现的叶绿体密切相关，并且许多生化过程是保守的。因此，蓝细菌已被广泛用作研究叶绿体相关过程的模型，例如参与光合作用的蛋白质成分如何工作。特别是蓝藻集胞藻 6803 是一种广泛使用的实验系统，因为在这种生物体中进行基因工程实验很容易。最近，Peter Nixon 及其同事发现了一种名为 FtsH2 的蓝藻蛋白酶，它参与光损伤后释氧光系统 II 复合体的修复。 FtsH2 的同系物也参与叶绿体中的相同过程。随后，FtsH2 已被证明参与集胞藻 6803 成功适应许多其他环境胁迫，包括热、高盐和无机碳可用性降低。因此，FtsH2 是控制许多对蓝藻生存至关重要的不同生理过程的重要因素。在本提案的背景工作中，我们开发了实验工具来对此类 FtsH 蛋白酶进行重要的基础研究。我们开发了纯化 FtsH2 蛋白酶的技术，并证明它与相关的 FtsH3 蛋白酶形成复合物。通过使用电子显微镜，我们首次证明该 FtsH2/FtsH3 复合物由六个亚基组成。在本申请中，我们描述了一系列实验来评估 FtsH2 以及集胞藻 6803 中发现的 FtsH 蛋白酶家族的其他三个成员的结构和功能。我们建议识别每个 FtsH 亚基在细胞中的位置，确定细胞中不同类型 FtsH 复合物的数量和组成，确定每种 FtsH 蛋白酶的潜在靶标，并确定该复合物是否表现出生理效应FtsH2 突变体是 FtsH 复合物的蛋白水解活性或 FtsH 复合物帮助拉动或重新折叠细胞靶标的能力的结果。除了提高我们对蓝藻如何应对各种环境胁迫的理解之外，我们的结果对于试图了解 FtsH 在叶绿体中的作用的植物科学家也具有特殊意义。最终，对 FtsH 蛋白酶的研究可能会产生光合生物，例如农作物，它们能够在包括强光胁迫在内的一系列环境条件下更高效地生长。

项目成果

Role of FtsH2 in the repair of Photosystem II in mutants of the cyanobacterium Synechocystis PCC 6803 with impaired assembly or stability of the CaMn(4) cluster.

FtsH2 在修复 CaMn(4) 簇组装或稳定性受损的蓝藻集胞藻 PCC 6803 突变体光系统 II 中的作用。

• DOI: 10.1016/j.bbabio.2010.02.006
• 发表时间: 2010-05-01
• 期刊: Biochimica et biophysica acta
• 作者: J. Komenda;J. Knoppová;Vendula Krynická;P. Nixon;M. Tichý
• 通讯作者: M. Tichý

Subunit composition of CP43-less photosystem II complexes of Synechocystis sp. PCC 6803: implications for the assembly and repair of photosystem II.

集胞藻属无 CP43 光系统 II 复合物的亚基组成。

• DOI: http://dx.10.1098/rstb.2012.0066
• 发表时间: 2012
• 期刊: Philosophical transactions of the Royal Society of London. Series B, Biological sciences
• 作者: Boehm M

The Psb27 assembly factor binds to the CP43 complex of photosystem II in the cyanobacterium Synechocystis sp. PCC 6803.

Psb27 组装因子与蓝藻集胞藻属光系统 II 的 CP43 复合物结合。

• DOI: http://dx.10.1104/pp.111.184184
• 发表时间: 2012
• 期刊: Plant physiology
• 影响因子: 7.4
• 作者: Komenda J

Assembling and maintaining the Photosystem II complex in chloroplasts and cyanobacteria.

在叶绿体和蓝细菌中组装和维持光系统 II 复合体。

• DOI: http://dx.10.1016/j.pbi.2012.01.017
• 发表时间: 2012
• 期刊: Current opinion in plant biology
• 影响因子: 9.5
• 作者: Komenda J

Investigating the early stages of photosystem II assembly in Synechocystis sp. PCC 6803: isolation of CP47 and CP43 complexes.

研究集胞藻光系统 II 组装的早期阶段。

• DOI: http://dx.10.1074/jbc.m110.207944
• 发表时间: 2011
• 期刊: The Journal of biological chemistry
• 作者: Boehm M