Structural characterization of malic enzyme of Trypanosoma cruzi and inhibitor discovery by a High-Throughput Screening assay.

Abstract

American trypanosomiasis is an infectious disease caused by the protozoan Trypanosoma cruzi. The acute phase is the only stage with treatment, which is made with highly toxic drugs . The research of novel metabolic targets might lead to the development of new effective drugs to the chronic phase of the disease. Enzymes that produce NADPH are considered promising targets, since the reduction of NADPH levels of the parasites affects as much their growth as their defense against oxidative attack caused by the mammalian host immune system. This way, dehydrogenases which reduce NADP+ can be interesting drug targets, being the enzymes of the pentose phosphate pathway, like glucose-6-phosphate dehydrogenase (G6PD), the main producers when the parasite uses glucose as the carbon source, what takes place when the parasite is at the bloodstream of the mammalian host. However, inside the cell, the parasite changes its metabolism to degradation of aminoacids, becoming other enzymes important too, like malic enzyme and isocitrate dehydrogenase. This project is focused on structural characterization of the malic enzyme of T. cruzi and on discovery of new inhibitors that can be used as chemical probes to study the inhibition effect of this target in the parasite. Furthermore, we will take advantage of the crystallization system of G6PD developed during the Master's project, using it to study new inhibitors identified by the group.