Charakterisierung des PGRL1/FQR Enzyms auf genetischer, funktioneller und evolutionärer Ebene

PGRL1/FQR 酶在遗传、功能和进化水平上的表征

• 批准号: 248406100
• 负责人: Professor Dr. Dario Leister
• 金额: --
• 依托单位: Lehrstuhl für Molekularbiologie der Pflanzen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/248406100?language=en
• 关键词: Charakterisierung; des; PGRL1; FQR; Enzyms

Whereas linear electron flow is driven by both photosystems and produces ATP and NADPH, the cyclic electron flow (CEF) only generates ATP and is driven by photosystem I alone. We recently identified PGRL1 as a central component of the antimycin A (AA)-sensitive variant of CEF and found that Arabidopsis PGRL1 is a redox-active protein which actually acts in vitro, together with PGR5, as the long sought ferredoxin-plastoquinone reductase (FQR). Interestingly, the complexity of PGRL1/PGR5-dependent CEF seems to have gradually evolved from a process that involves PGR5 (and most likely an as yet not identified protein with PGRL1-like function) in a AA-sensitive manner in Synechocystis (a model for the endosymbiont giving rise to the chloroplast), to mechanisms that rely on both proteins, either involving a PGRL1- and PGR5-containing supercomplex lacking AA-sensitivity (in Chlamydomonas, a model for unicellular organisms with chloroplasts) or as an AA-sensitive PGRL1-PGR5 heterodimer (in Arabidopsis, a model for multicellular land plants). In this project, we wish to reconstruct the evolution of the function of PGRL1 and PGR5, thereby resolving the functional discrepancies which apparently exist between land plants (Arabidopsis), green algae (Chlamydomonas) and cyanobacteria (Synechocystis). To this end, we employ the cyanobacterium Synechocystis to reconstruct and characterise the protein complexes that mediate the flowering-plant- and green-alga- types of CEF, as well as to identify the functional analogue of PGRL1 (PRIO) in Synechocystis, for the existence of which we obtained strong evidence in preliminary work. By systematically identifying and characterising suppressor mutations that can compensate the effects of the pgr5 mutation in Arabidopsis, we will dissect the interplay of the PGRL1/PGR5 pathway with other electron transport pathways in the flowering plant Arabidopsis. To achieve these goals, we will focus on seven sub-projects.

线性电子流由两个光系统驱动并产生 ATP 和 NADPH，而循环电子流 (CEF) 仅产生 ATP，并仅由光系统 I 驱动。我们最近发现 PGRL1 是 CEF 抗霉素 A (AA) 敏感变体的核心成分，并发现拟南芥 PGRL1 是一种氧化还原活性蛋白，实际上与 PGR5 一起在体外发挥作用，作为长期寻找的铁氧还蛋白质体醌还原酶。 FQR）。有趣的是，PGRL1/PGR5 依赖性 CEF 的复杂性似乎是从集胞藻（集胞藻的模型）中以 AA 敏感方式涉及 PGR5（很可能是一种尚未识别的具有 PGRL1 样功能的蛋白质）的过程逐渐演变而来的。产生叶绿体的内共生体），依赖于这两种蛋白质的机制，要么涉及含有 PGRL1 和 PGR5 的缺乏 AA 敏感性的超级复合物（在衣藻中，具有叶绿体的单细胞生物模型）或作为 AA 敏感的 PGRL1-PGR5 异二聚体（在拟南芥中，多细胞陆地植物模型）。在这个项目中，我们希望重建PGRL1和PGR5功能的进化，从而解决陆地植物（拟南芥）、绿藻（衣藻）和蓝藻（集胞藻）之间明显存在的功能差异。为此，我们利用蓝藻集胞藻来重建和表征介导 CEF 的开花植物和绿藻类型的蛋白质复合物，并鉴定集胞藻中 PGRL1 (PRIO) 的功能类似物，用于我们在前期工作中获得了强有力的证据。通过系统地鉴定和表征拟南芥中可以补偿 pgr5 突变影响的抑制突变，我们将剖析开花植物拟南芥中 PGRL1/PGR5 途径与其他电子传递途径的相互作用。为了实现这些目标，我们将重点关注七个子项目。