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，人们对这些藻类光合作用的调节知之甚少。我们已经能够证明，在硅藻中(与陆地植物相反)，卡尔文循环中的几种酶不是通过硫氧还蛋白进行氧化还原调节的。在对三角褐指藻基因组的注释过程中，我们能够识别出几个编码硫氧还蛋白的基因，这些基因被定位到质体中，令人惊讶的是，其中包括一个硫氧还蛋白h，它在其他生物中只在细胞质中发现。此外，我们还发现几种Calvin循环酶是由多个(最多四个)基因拷贝编码的。在这个项目中，我们希望通过对关键酶的基因表达和酶特性的分析来研究硅藻中Calvin循环的调节。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.