The great majority of ophidian accidents in Brazil are caused by Bothrops genus snakes. Myonecrosis, which is not well neutralized by administration of antiophidian serum, is one of the consequences of these accidents. The vaster protein component of bothropic venom and one of the main responsibles for muscular necrosis is the phospholipases A2 myotoxic (PLA2s). These toxins may be classified in PLA2s or Asp49-PLA2s, whose myotoxic mechanism in the envenoming is related to the catalytic process, and in homologue PLA2s or Lys49-PLA2s, whose structure is similar to PLA2s, although myotoxic mechanism is not related to catalysis and is not well known. On the other hand, some Asp49-PLA2s share the characteristic of homologue PLA2s to exert myotoxic independent of catalysis. Thus, the objective of this project is to understand this mechanism, the myotoxic independent of catalysis, by studies of the bothropic myotoxins BthTX-II e PrTX-III (two basic Asp-PLA2s) and BthTX-I (homologue PLA2) in native and complexed states. To achieve it, we will perform structural studies (X-ray crystallography and Small-angle X-ray scattering) and theoretical (Normal mode molecular dynamics). Beyond that, the generated models and data will be used to extend the scope of the novel ab initio crystallographic method, ARCIMBOLDO, to test and optimize it in the scenario of using different models from normal mode molecular dynamics and exploting structural units different from the currently used secondary structure elements. In summary, the results of this project intend to aid myotoxic mechanism comprehension and the complementation of antiofidian serum with the inhibitors studied, or posteriorly with drug design, and optimize the ab initio method to other crystallographic determinations.
News published in Agência FAPESP Newsletter about the scholarship: