Intracellular Degradation of SARS-CoV-2 N-protein Caused by Modular Nanotransporters Containing Anti-N-protein Monobody and a Sequence that Recruits the Keap1 E3 Ligase

In addition to nucleic acids, various viral proteins are involved in the assembly of virion. If it is possible to create a biologically active agent that leads to the degradation of one of the key proteins for virus assembly and/or destroys the viral factory, then this agent will effectively cope with virus replication. One of these key proteins for the SARS-CoV-2 virus is the nucleocapsid protein (N-protein). As such a bioactive agent, we offer a modular nanotransporter (MNT) developed by us, which, in addition to an antibody mimetic to the N-protein, contains an amino acid sequence for the attraction of the Keap1 E3 ubiquitin ligase. This should lead to the subsequent degradation of the N-protein. We have shown that functional properties of modules within the MNT permit its internalization into target cells, endosome escape into the cytosol, and binding to the N-protein. Using flow cytometry and Western blot, it was demonstrated that significant degradation of N-protein is observed when A549 and A431 cells transformed with N-protein are incubated with the developed MNTs. The proposed MNTs open up a new approach for the treatment of viral diseases.