Engineering a Plant Viral Coat Protein for In Vitro Hybrid Self-Assembly of CO₂-Capturing Catalytic Nanofilaments

Plant virus-based nanoparticles are used as self-assembled protein scaffolds for the construction of enzyme nanocarriers. To date, one-pot production and coupling of both enzymes and scaffolds by genetic conjugation have been demonstrated only in plants. Herein, we report bacterial production and in vitro self-assembly of nanofilaments for CO₂ capture. Filamentous virus-like particles (VLPs) were successfully formed by genetically fusing carbonic anhydrase from Hydrogenovibrio marinus (hmCA) to the N terminus of the coat protein (CP_PVY) of potato virus Y with a flexible linker. The instability of VLPs against proteolytic degradation was circumvented by the periplasmic export of the fusion protein. The truncated form of CP_PVY coexpressed by internal translation was crucial for the successful formation of long filamentous VLPs by alleviating steric hindrance via hybrid assembly. The fast and economic bottom-up fabrication of highly active nanobiocatalyst allows the nanofilaments to be efficiently used and recovered in potential biocatalytic and biosensor systems.