Rubisco regulation in response to altered carbon status in the cyanobacterium Synechococcus elongatus PCC 7942
Rubisco regulation in response to altered carbon status in the cyanobacterium Synechococcus elongatus PCC 7942
复制标题
Rubisco 调节响应蓝细菌细长聚球藻 PCC 7942 中碳状态的改变
DOI：
10.1093/plphys/kiac065
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发表时间：
2022
期刊：
影响因子：
7.4
通讯作者：
Ducat, Daniel C.
中科院分区：
文献类型：
--
作者：
Singh, Amit K.;Santos-Merino, María;Sakkos, Jonathan K.;Walker, Berkley J.;Ducat, Daniel C.
光合生物具有多种机制来实现吸收的光（源）和代谢利用或耗散这种能量（汇）的能力之间的平衡。虽然检测代谢状态/平衡变化的调节过程在植物中得到了相对较好的研究，但光合微生物中的类似途径仍缺乏特征。在这里，我们探讨了系统的变化，导致改变的碳供应模式蓝藻Synechococcus elongatusPCC 7942通过利用工程菌株的中心碳代谢产物，蔗糖的流入/流出，可以调节实验。我们观察到，高通量蔗糖输出途径的诱导导致内部碳储存池（糖原）的消耗和光合活性的估计同时增加。此外，蛋白质组范围的分析和基于荧光标记的分析表明，上调的因素后，激活的代谢库集中在核酮糖-1，5-二磷酸羧化酶-加氧酶（Rubisco）和辅助模块参与Rubisco成熟。羧化体的数量和Rubisco活性也增加了以下参与蔗糖分泌。相反，通过异源转运蛋白喂饲外源蔗糖来逆转蔗糖的通量导致糖原库增加、Rubisco丰度降低和羧基体重组。我们的数据表明，Rubisco活性和组织是连接到参与代谢平衡的蓝藻调控途径的关键变量。
Photosynthetic organisms possess a variety of mechanisms to achieve balance between absorbed light (source) and the capacity to metabolically utilize or dissipate this energy (sink). While regulatory processes that detect changes in metabolic status/balance are relatively well studied in plants, analogous pathways remain poorly characterized in photosynthetic microbes. Here, we explored systemic changes that result from alterations in carbon availability in the model cyanobacteriumSynechococcus elongatusPCC 7942 by taking advantage of an engineered strain where influx/efflux of a central carbon metabolite, sucrose, can be regulated experimentally. We observed that induction of a high-flux sucrose export pathway leads to depletion of internal carbon storage pools (glycogen) and concurrent increases in estimates of photosynthetic activity. Further, a proteome-wide analysis and fluorescence reporter-based analysis revealed that upregulated factors following the activation of the metabolic sink are concentrated on ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) and auxiliary modules involved in Rubisco maturation. Carboxysome number and Rubisco activity also increased following engagement of sucrose secretion. Conversely, reversing the flux of sucrose by feeding exogenous sucrose through the heterologous transporter resulted in increased glycogen pools, decreased Rubisco abundance, and carboxysome reorganization. Our data suggest that Rubisco activity and organization are key variables connected to regulatory pathways involved in metabolic balancing in cyanobacteria.