Functional Characterization of Methionine Sulfoxide Reductase from Trypanosoma cruzi

ARIAS, DIEGO G.; CABEZA, MATÍAS S.; ECHARREN, MA. LAURA; IGLESIAS, ALBERTO A.; GUERRERO, SERGIO A.

Mendoza

Congreso; XLVIII Reunión Anual de la SAIB; 2012

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Methionine is an amino acid susceptible to be oxidized to methionine sulfoxide (MetSO). Reduction of MetSO to methionine is catalyzed by methionine sulfoxide reductase (MSR), an enzyme present in almost all organisms. In trypanosomatids, the study of antioxidant systems has been mainly focused on the involvement of trypanothione, a specific redox component in these organisms. However, poorly information is available concerning their mechanisms for repairing oxidized proteins, which would be relevant for the survival of these pathogens in the various stages of their life cycle. Recently, we characterized two A-type MSR proteins from and . In this work, we report the molecular cloning of a gene encoding a putative B type MSR. The gene was expressed in , and the corresponding recombinant protein was purified and functionally characterized. The enzyme was specific for L-Met( )SO reduction, using TXNI, TXNII and TRX as the reducing substrates. In addition, we found that MSRB could compensate for MSR deficiency in yeast mutant strain lacking both MSRA and MSRB genes. The protein presented redox-dependent change in monomer/dimer oligomerization states. The results support the occurrence of a metabolic pathway in involved in the critical function of repairing oxidized macromolecules.