Biochemical and functional characterization of a hybrid cluster protein from Entamoeba histolytica.

BENTIVEGNA S; GUERRERO SA; IGLESIAS AA; ARIAS DG

Congreso; SAIB LI Reunión anual; 2015

Entamoeba histolytica, an intestinal parasite that is the causative agent of amoebiasis, is exposed to elevated amounts of highly toxic reactive oxygen and nitrogen species during tissue invasion. Hybrid cluster proteins (HCP) contain two types of Fe/S clusters, namely a [4Fe-4S] or [2Fe-2S] cluster and a novel type of hybrid cluster, [4Fe 2S-2O]. While it was proposed that HCP acts in some step of nitrogen metabolism in bacteria, a specific role for this protein remained unknown. In this work, we present functional data and structural properties of HCP from E. histolytica (EhHCP). We employed an E. coli-based functional complementation assay to rescue phenotypes of hcp mutant strain. The complementation experiments with recombinant HCP demonstrate that the Δhcp E. coli strain can suppress the sensitivity to hydrogen peroxide or hydroxylamine. Furthermore, ferredoxin from E. histolytica and rubredoxin from Clostridium pasteurianum were reducing substrates for recombinat EhHCP in vitro. Altogether, the results suggest that HCP could be involved in oxidative and nitrosative stress protection in the parasite. To the best of our knowledge this is the first characterization of a eukaryotic HCP. Granted by UNL, CONICET (PIP112 2011 0100439, PIP114-2011-0100168) and ANPCyT (PICT2012-2439, PICT2013-0253)89