3D modeling of malarial and neosporosis otu deubiquitinases and identification of novel otu inhibitors for therapy

3D MODELING OF MALARIAL AND NEOSPOROSIS OTU DEUBIQUITINASES AND IDENTIFICATION OF NOVEL OTU INHIBITORS FOR THERAPY Malaria is a potentially lethal infectious disease caused by Plasmodium parasites. The parasites are transmitted to people by female Anopheles mosquitoes. Almost half of the world population are at risk of malaria disease. Parasites acquired resistance to all available drug therapies therefore there is need for effective treatment. The survival of viruses, which are mandatory intracellular parasites such as CCHFV, depends on the invasion of the host cell after antagonizing the NF-κB signaling pathways. Crimean Congo Hemorrhagic Fever Virus (CCHFV) performs intracellular invasion using viral OTU protease with extensive deconjugation activity. Inhibition of this viral OTU protein is associated with the Y89-W99 package. Interestingly, conserved aminoacids in malaria and Neospora parasites which correspond to OTU domain in CCHFV were found in this project. It was suggested that malaria and Neospora parasites can perform their activities by antagonizing the NF-κB pathway using the deconjugation feature of OTU proteins. In this project it was hypothesized that OTU proteins could be a key target in malaria and it was aimed to discover inhibitors targeting these OTU proteins as candidate drugs in malaria. The project contains both in silico, in vitro and in vivo studies. Here for the first time, novel OTU deubiquitinases of three different malaria strains and Neospora parasites were 1) modeled three-dimensionally, 2) produced recombinantly, 3) characterized and their DUB activities were proved in vitro and in vivo. Moreover, it was shown how the new OTU proteins manipulate both the innate immune pathways and the cell mono-Ub and polyUb levels. A library containing about 5.000.000 of compounds was prepared and these comppounds were targeted against OTU DUBs. Based on docking scores, druggabilities, ADME-tox features, IC50 values, DUB inhibitory characteristics even at micro level concentrations, effects of the molecule treatments on expression in both RNA and protein level, four molecules were discovered. In conclusion, best candidate drug molecules against malaria disease which has no commercial vaccine, specific drug or approved treatment to date, were found.