FERREDOXIN FROM Trypanosoma cruz; AND ITS POTENTIAL ROLE IN BIOREDUCTION OF ANTIPROTOZOAL COMPOUNDS

GIRARDINI J.E.; MANARÍN R.; SERRA E.

Bariloche, Argentina

Congreso; XXXIX Reunión Anual de la Sociedad Argentina de Bioquímica y Biología molecular - SAIB; 2003

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.1pt 792.1pt; margin:36.0pt 328.65pt 36.0pt 36.0pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Ferredoxins (Frd) act as low potential electron carriers. This pro­teins can be classified according to their structure and the type and number of Fe-S clusters that contain. Vertebrate type ferredoxins contain one [2Fe2S] cluster and they are present in a wide variety of organisms, including prokariotes. Its biological function is poorly understood. In mammals, they are involved in the biosynthesis of steroids in mitochondria. However, the presence of this protein, and its reducing partner ferredoxin-NADP(H) oxidoreductase (FNR), in organisms incapable of sinthetizing steroids suggests that they may perforrn another function. They were implicated in and Fe-S cluster assembly in yeasts, in the metabolization ofxenobiotics in prokaryotes and in induction of apoptosis in human cell lines. The observation that mammalian Frd and FNR can reduce in vitro compounds with antiprotozoal activity prompted us to search for this kind of enzymes in T. cruzi. We have previously identified sequences that code for FNR (TcFNR) and Frd (TcFrd). In the present work recombinant TcFrd was expressed fused to thioredoxin from Escherichia coli. The [2fe-2S] cluster was characterized by UV-visible spectroscopy and circular dichroism. The expression of the enzyme in T cruz; was analyzed by northem blot and west­em blot. We were able to confirrn the ability of the recombinant enzyme to act as electron carrier. This results make TcFrd an inter­est candidate for the bioactivation of trypanocidal compounds.