Construção e caracterização in silico de uma proteína multiepitópica para diagnóstico de paracoccidioidomicose

Abstract

Paracoccidioidomycosis is a systemic mycosis caused by fungi of the Paracoccidioides spp. genus, with an incidence of 3360 to 5600 cases per year and is one of the most common systemic mycosis in Brazil. Although there is treatment for the disease, the improvement in the clinical picture is linked to an early diagnosis, however, there isn’t a standardized and effective diagnostic method for the disease. An alternative to the diagnostic methods employed would be the use of a multi-epitopic protein containing epitopes from different sources in an indirect ELISA diagnostic modelt. In this work, we evaluated 23 peptide sequences (A - W) that were shown to be reactive against the serum of patients with paracoccidioidomycosis, according to the thesis of professor Luís Felipe Minozzo Figueiredo, and we selected those that showed the most promise. The objective was to evaluate sequences that didn’t show similarity with proteins from related disease-causing species, construct a multi-epitopic protein from these sequences, and characterize it by in silico analysis. From the in silico analysis, it was possible to determine that the most promising peptides were the peptides: B, H, K, M, N and W, which were used for the construction of the multiepitopic chimeric protein. The generated chimeric protein displayed several epitopic regions when subjected to epitope prediction analysis by the IEDB software, furthermore, it did not show similarity with related disease proteins. The generated chimeric protein did not present the signal peptide and was characterized as stable, showing α-helix and β-sheet conformation. In conclusion, it was possible to construct a promising protein sequence for an antigen to be used in a diagnostic kit for paracoccidioidomycosis, allowing the identification of the disease caused by different species and with low potential for generating cross reactions.