Regulation of CO2 fixation in diatom plastids

硅藻是具有重要生态意义的单细胞藻类。到目前为止，人们对这些藻类的光合作用的调节知之甚少。我们已经能够证明，在硅藻（与陆地植物相反）中，卡尔文循环的几种酶不通过硫氧还蛋白进行氧化还原调节。在硅藻三角褐指藻基因组的注释过程中，我们能够鉴定出几种编码靶向质体的硫氧还蛋白的基因，令人惊讶的是包括硫氧还蛋白h，其在其他生物体中仅在胞质溶胶中发现。此外，我们发现，几个卡尔文循环酶编码的多个（多达四个）基因拷贝。本研究通过对硅藻卡尔文循环关键酶的基因表达和酶学特性分析，探讨硅藻卡尔文循环的调控机制。此外，我们希望通过表达GFP融合蛋白来定位单个同工酶，并通过亲和层析来鉴定硫氧还蛋白的潜在靶点。

Diatoms are unicellular algae of great ecological importance. So far very little is known about the regulation of photosynthesis in these algae. We have been able to show that in diatoms (in contrast to land plants) several enzymes of the Calvin Cycle are not redox-regulated via thioredoxin. During the annotation of the genome of the diatom Phaeodactylum tricornutum we were able to identify several genes encoding thioredoxins that are targeted into the plastids, surprisingly including a thioredoxin h, which in other organisms is found exclusively in the cytosol. In addition we found that several Calvin cycle enzymes are encoded by multiple (up to four) gene copies. In this project we want to investigate the regulation of the Calvin cycle in diatoms by analysis of gene expression and enzymatic characterization of key enzymes. Furthermore we want to localize individual isoenzymes via expression of GFP-fusion proteins and to identify potential targets of thioredoxin by affinity chromatography.