Heme A biosynthesis in Trypanosoma cruzi, an essential cofactor for complex cytochrome c oxidase

MARCELO L MERLI; LUCÍA V FERRERO; JOSEFINA HERNÁNDEZ; JULIA A. CRICCO

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2012

Sociedad Argentina de Investigaciones en Bioquímicas y Biología Molecular

Trypanosoma cruzi, the etiological agent of the Chagas disease, presents nutritional requirements for heme. This parasite must acquire heme from different hosts and distribute it to the different hemeproteins. We are interested in elucidating the heme traffic to the mitochondrion and its conversion into heme A, the cofactor only seen in cytochrome c oxidase complex (CcO). It is assumed that the CcO is essential all along the life cycle of the parasite. In our lab, we identified the enzymes involved in heme A biosynthesis in T. cruzi: TcCox10 (heme O synthase) and TcCox15 (heme A synthase), and characterized their function in the yeast S. cerevisiae. The mRNA level of these genes were analyzed by qRT-PCR and they were detected along the different parasite life stages. We obtained specific antibodies against TcCox10 and TcCox15 and the presence of this proteins was observed in different life stages of the parasite by western blot analysis and their mitochondrial localization was analyzed by indirect immunofluorescence detection. We obtained nonfunctional proteins by site direct mutagenesis, overexpressed them in T. cruzi epimastigote and a dominant negative dominant effect was observed. These preliminary results indicate the relevance of this pathway, at least for the epimastigote stage, suggesting the heme A biosynthesis might be essential for T. cruzi parasite.