The molecular basis of D1 degradation and photosystem two repair

D1降解与光系统二次修复的分子基础

• 批准号: BB/E006388/1
• 负责人: Peter Nixon
• 金额: $ 43.74万
• 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: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FE006388%2F1
• 关键词: molecular; basis; D1; degradation; photosystem

Plant growth is exquisitely sensitive to the intensity of light in the environment. At low light intensities, growth is limited because of insufficient light to drive photosynthesis. At higher intensities, growth becomes inhibited because of the damaging effects of light on the photosynthetic apparatus found in the chloroplast. This phenomenon of photoinhibition has a profound effect on crop yields especially when plants are subjected to high light in combination with other stress conditions such as heat and water stress. One of the targets of light damage in the chloroplast is the photosystem two complex, which is involved in water oxidation and photosynthetic electron transport, and in particular the D1 protein. Plants have developed a repair mechanism to replace damaged D1 by a newly synthesised copy. Under most conditions this repair mechanism allows PSII activity to be maintained. However at high light intensities the rate of repair is unable to match the rate of damage to PSII and under these conditions there is a net loss of PSII activity and photosynthetic performance. In principle, improving the repair mechanism is one route by which more light-resistant plants can be generated. As yet the molecular details of PSII repair are unclear, especially the process by which damaged D1 is removed from the membrane. Recently we discovered the identity of a particular class of protease (FtsH proteases) that was needed for D1 degradation. We have also discovered that the N-terminus of D1 is important for D1 degradation in cyanobacteria, which are closely related to chloroplasts. This has led us to postulate a mechanism for D1 degradation that involves the recognition of the N-terminus of damaged D1 by the FtsH protease. Our hypothesis is at odds with the current model in the scientific literature. In this proposal we have designed a series of experiments to differentiate between the two models. Ultimately the results of this work will provide a clearer picture of PSII repair in plants.

植物的生长对环境中的光照强度极其敏感。在低光照强度下，生长受到限制，因为没有足够的光来驱动光合作用。在较高的强度下，生长受到抑制，因为光对叶绿体中的光合机构有破坏作用。这种光抑制现象对作物产量具有深远的影响，特别是当植物受到强光与其他胁迫条件如热和水胁迫的组合时。叶绿体中光损伤的目标之一是光系统2复合物，其参与水氧化和光合电子传递，特别是D1蛋白。植物已经发展出一种修复机制，用新合成的复制品取代受损的D1。在大多数情况下，这种修复机制允许PSII活性得以维持。然而，在高光强下，修复的速度是无法匹配的速度损坏PSII和在这些条件下，有一个净损失的PSII活性和光合性能。原则上，改善修复机制是可以产生更多耐光植物的途径之一。到目前为止，PSII修复的分子细节尚不清楚，特别是受损的D1从膜上去除的过程。最近，我们发现了D1降解所需的一类特殊蛋白酶（FtsH蛋白酶）的身份。我们还发现，D1的N-末端是重要的D1降解蓝藻，这是密切相关的叶绿体。这使我们假设的机制D1降解，涉及识别的N-末端受损D1的FtsH蛋白酶。我们的假设与科学文献中的当前模型不一致。在这个提议中，我们设计了一系列实验来区分这两种模型。最终，这项工作的结果将提供一个更清晰的图片PSII修复植物。

项目成果

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

CP43无光系统II的亚基组成，Synechocystis sp。 PCC 6803：对光系统II的组装和修复的影响。

• DOI: 10.1098/rstb.2012.0066
• 发表时间: 2012-12-19
• 期刊: Philosophical transactions of the Royal Society of London. Series B, Biological sciences
• 作者: Boehm M;Yu J;Reisinger V;Beckova M;Eichacker LA;Schlodder E;Komenda J;Nixon PJ
• 通讯作者: Nixon PJ

Structural analysis of an FtsH2/FtsH3 complex isolated from Synechocystis sp. PCC 6803

从集胞藻中分离的 FtsH2/FtsH3 复合物的结构分析。

• 发表时间: 2008
• 作者: Barker M

Testing the Role of the N-Terminal Tail of D1 in the Maintenance of Photosystem II in Tobacco Chloroplasts.

• DOI: 10.3389/fpls.2016.00844
• 发表时间: 2016
• 期刊: Frontiers in plant science
• 影响因子: 5.6
• 作者: Michoux F;Ahmad N;Wei ZY;Belgio E;Ruban AV;Nixon PJ
• 通讯作者: Nixon PJ