| Popis: |
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 cyanobacteriumSynechocystissp. PCC 6803 and the fast-growing cyanobacterial strainSynechococcus elongatusUTEX 2973. Transmission electron microscopy and electron tomography demonstrated that overexpression of a modified bacterial microcompartment shell protein, PduA*, led to the generation of bundles of longitudinally aligned nanofilaments inS. elongatusUTEX 2973 and shorter filamentous structures inSynechocystissp. 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 only had a minor impact on cellular metabolism. Finally, we targeted the fluorescent reporter mCitrine to the nanofilaments using an encapsulation peptide that natively interacts with PduA. To our knowledge, this is the first study to apply bacterial microcompartment based nanotechnology in cyanobacteria. The establishment of nanofilaments in cyanobacterial cells is an important step towards cellular organization of heterologous pathways and the establishment of cyanobacteria as next generation hosts. |
