Dynamic organization of glycolytic routes and the Calvin-Benson-Bassham cycle during the autotrophy-heterotrophy switch

在反方向操作的过程是高度交织在中央碳水化合物代谢的蓝藻聚囊藻sp. PCC 6803。糖酵解途径，以分解代谢方向代谢碳水化合物，与Calvin-Benson-Bassham （CBB）循环共享几种酶和反应，后者以合成代谢方式运作。这些相反的过程在空间上是不分离的，因为蓝藻是没有任何进一步分隔的原核生物。由于二氧化碳通过CBB循环的固定是由光下的光合作用驱动的，而糖酵解途径对于黑暗中碳水化合物的分解代谢利用至关重要，因此在自养异养的光暗切换过程中，这两个过程在时间上是分开的。然而，与我们的合作伙伴Forchhammer和Wittmann一起，我们可以证明糖酵解途径在自养条件下也同样重要。它们在过渡状态下形成分流，补充和微调CBB循环。为此，内部糖原储存库被用作碳水化合物来源。entert - doudoroff （ED）通路和氧化戊糖磷酸酯（OPP）通路的关键酶参与这些分流，而Emden-Meyerhoff-Parnas （EMP）通路不参与。我们计划进一步研究围绕CBB循环的糖酵解途径的微调，并特别检查这些过程是否在细胞的空间水平上显示出动态组织。除此之外，我们与合作伙伴Hagemann和Forchhammer一起对ED通路缺失的突变体（Δeda）进行了生理表征，发现与野生型（WT）相比，存在一些表型差异。这些发现在一定程度上与通量分析相矛盾。因此，我们计划检查，观察到的Δeda表型是否完全依赖于Eda的缺失，或者其他调控单元，如非编码rna，是否在突变体构建过程中被沉默，这可能是导致观察到的与WT差异的原因。此外，我们想检查Eda是否可能具有月光功能，或者可能参与中枢碳水化合物代谢的微调动态过程

Processes that operate in opposite directions are highly intertwined in the central carbohydrate metabolism of the cyanobacterium Synechocystis sp. PCC 6803. Glycolytic routes, that metabolize carbohydrates in catabolic direction, share several enzymes and reactions with the Calvin-Benson-Bassham (CBB) cycle, which operates anabolically. These opposing processes are not separated spatially, as cyanobacteria are prokaryotes without any further compartmentation. As the fixation of CO2 via the CBB cycle is driven by photosynthesis in the light, whereas glycolytic routes are of importance for the catabolic utilization of carbohydrates in darkness, both processes are separated time-wise during the autotrophy heterotrophy switch between light and darkness. However, together with our cooperation partners Forchhammer and Wittmann, we could show that glycolytic routes are as well of importance under autotrophic conditions. They form shunts in transition states that replenish and fine-tune the CBB cycle. For this, internal glycogen reservoirs are utilized as carbohydrate sources. Key enzymes of the Enter-Doudoroff (ED) pathway and the oxidative pentose phosphat (OPP) pathway participate in these shunts whereas the Emden-Meyerhoff-Parnas (EMP) pathway is not involved. We plan to investigate the fine-tuning of glycolytic routes und the CBB cycle further and to examine particularly, if these processes show a dynamic organization on a spatial level in the cells. Apart from that, the physiologic characterization of a mutant (Δeda) with deleted ED pathway together with our cooperation partners Hagemann and Forchhammer revealed several phenotypic differences in comparison to the wild type (WT). These findings are partly contradictory to flux analyses. We therefore plan to check, if the observed phenotypes of Δeda rely exclusively on the deletion of Eda, or whether other regulatory units as e.g. noncoding RNAs were silenced during the construction of the mutant which might be responsible for the observed differences to the WT. In addition, we want to check if Eda might have moonlight functions or might participate in dynamic processes for the fine-tuning of the central carbohydrate metabolism