Biogenesis of thylakoid membranes in cyanobacteria

类囊体膜（TM）代表通过蛋白质/色素复合物光系统II（PSII）、Cytb 6 f和光系统I（PSI）进行能量产生光合电子传递的位点。虽然这种分子机器的结构和工作模式已经很好地理解，但对其在个体发育过程中的发展知之甚少。本研究项目致力于阐明蓝藻模式系统集胞藻PCC 6803中TM生物发生的时空组织。作为一个案例研究，我们将专注于组装PSII，特别是其氧气的锰簇，我们最近被假定发生在专门的生物合成中心靠近质膜。在这方面，周质PratA因子以及阅读框slr 0483的基因产物似乎起重要作用。虽然三肽重复序列（TPR）蛋白PratA转运锰，因此直接参与PSII的水裂解装置的成熟，根据最新的超微结构研究，膜蛋白Slr 0483 p似乎是生物发生中心形成所必需的。计划工作的目标是详细了解分子工作模式以及这些因素通过应用分子遗传学，生物化学/生物物理学和电子显微镜方法。此外，其他因素，如最近确定的PratA相互作用伙伴，即，Slr 1277 p和Deg-protease HhoA将分析它们的功能和亚细胞定位。平行的PratA/D1复合物的X-射线结构分析将揭示PSII的D1蛋白的锰吸收过程的细节。这项工作将补充生化分析PratA相关的因素，从绿色藻类和维管植物测试的进化保守的锰交付PSII。

The thylakoid membrane (TM) represents the site of the energy-producing photosynthetic electron transport via the protein/pigment complexes photosystem II (PSII), Cytb6f and photosystem I (PSI). While the structure and working mode of this molecular machine is well understood, less is known about its development during ontogenesis. This research project is dedicated to the elucidation of the spatial/temporal organization of TM biogenesis in the cyanobacterial model system Synechocystis sp. PCC 6803. As a case study, we will focus on the assembly of PSII, especially its oxygen-evolving manganese cluster, which we have recently been postulated to take place in specialized biogenesis centers close to the plasma membrane. In this regard, the periplasmic PratA factor as well as the gene product of reading frame slr0483 seem to play essential roles. While the tetratricopeptide repeat (TPR) protein PratA transports manganese and, thus, is directly involved in the maturation of the water splitting apparatus of PSII, the membrane protein Slr0483p appears to be generally required for the formation of biogenesis centers based on latest ultrastructural investigations.The goal of the planned work is to gain detailed insights into the molecular working mode as well as the spatial organization of these factors by applying molecular genetical, biochemical/biophysical and electron microscopical methods. In addition other factors like the recently identified PratA interaction partners, i.e., Slr1277p and the Deg-protease HhoA will be analyzed in regard to their function and subcellular localization. Parallel X-ray structure analysis of the PratA/D1 complex will reveal details of the manganese uptake process by the D1 protein of PSII. This work will be complemented by biochemical analyses of PratA-related factors from green algae and vascular plants to test for an evolutionary conserved manganese delivery to PSII.