Abstract EN:

My thesis focuses on the analysis and structural study of viral nucleoproteins of Arenavirus and MERS-CoV, and the development of a therapeutic strategy against Arenaviridae Exo- and Endo-ribonuclease (Exo-NP and Endo). Nucleoproteins (NPs) are involved in protection and compaction of viral genome. In RNA-negative viruses, NP is part of replication complex, while in positive RNA viruses, its presence is exceptional and is common in Coronaviruses. NPs polymerize on contact with genomic RNA. Firstly, I performed an exhaustive analysis of NPs of Arenaviridae and Bunyavirales, and proposed a universal mechanism of polymerization by an "arm" extension, and then I structurally characterized the domain that assembles the MERS-CoV nucleoprotein polymer. Secondly, I developed viral nuclease inhibitors (Exo-NP and Endo). In Arenaviridae, the Exo-NP domain of NP is involved in the escape mechanism of the virus from innate immunity, and the Endo domain of the L protein is involved in the mechanism of cap snatching, the first step of transcription. The two nucleases, although structurally different, possess the same two metal ions molecular catalytic mechanism. The strategy is the identification of molecules targeting the catalytic site by ion docking, depletion. Using a virtual screening, crystallography and enzymatic characterization approach, I identified a molecule and characterize its inhibition on Exo-NP, thus validated the strategy. Unfortunately, the molecule showed toxicity in infected cells, it was not pursued. Finally, I applied this approach to a library of compounds on Exo-NP and Endo, and idetified molecules for development of inhibitors against Mammarenaviral nucleases.