PDF(Pubmed)
Abstract：
Cyanobacteria offer great potential as alternative biotechnological hosts due to their photoautotrophic capacities. However, in comparison to established heterotrophic hosts, several key aspects, such as product titers, are still lagging behind. Nanobiotechnology is an emerging field with great potential to improve existing hosts, but so far, it has barely been explored in microbial photosynthetic systems. Here, we report the establishment of large proteinaceous nanofilaments in the unicellular model cyanobacterium Synechocystis sp. PCC 6803 and the fast-growing cyanobacterial strain Synechococcus elongatus UTEX 2973. Transmission electron microscopy and electron tomography demonstrated that expression of pduA*, encoding a modified bacterial microcompartment shell protein, led to the generation of bundles of longitudinally aligned nanofilaments in S. elongatus UTEX 2973 and shorter filamentous structures in Synechocystis sp. PCC 6803. Comparative proteomics showed that PduA* was at least 50 times more abundant than the second most abundant protein in the cell and that nanofilament assembly had only a minor impact on cellular metabolism. Finally, as a proof-of-concept for co-localization with the filaments, we targeted a fluorescent reporter protein, mCitrine, to PduA* by fusion with an encapsulation peptide that natively interacts with PduA. The establishment of nanofilaments in cyanobacterial cells is an important step toward cellular organization of heterologous pathways and the establishment of cyanobacteria as next-generation hosts.
摘要：
蓝细菌由于其光合自养能力而具有作为替代生物技术宿主的巨大潜力。然而,与已建立的异养宿主相比，几个关键方面，如产品滴度，仍然落后。纳米生物技术是一个新兴的领域，具有巨大的潜力，以改善现有的宿主，但到目前为止,它在微生物光合系统中几乎没有被探索过。这里,我们报告了在单细胞模型蓝细菌集胞藻中建立大型蛋白质纳米丝。PCC6803和快速生长的蓝细菌菌株延伸神经球菌UTEX2973。透射电子显微镜和电子层析成像表明，pduA*的表达，编码修饰的细菌微室壳蛋白，导致在S.elongatusUTEX2973中产生纵向排列的纳米丝束，并在集胞藻中产生较短的丝状结构。PCC6803。比较蛋白质组学显示,PduA*比细胞中第二丰富的蛋白质丰富至少50倍,并且纳米丝组装对细胞代谢仅有较小的影响。最后,作为与细丝共同定位的概念证明，我们瞄准了一个荧光报告蛋白，mCitrine,通过与与PduA天然相互作用的封装肽融合到PduA*。蓝藻细胞中纳米丝的建立是朝着异源途径的细胞组织和蓝藻作为下一代宿主的建立迈出的重要一步。
