Biochemical and functional characterization of a monothiolic glutaredoxin from Trypanosoma cruzi

ODDI SL; MÁRQUEZ VE; GUERRERO SA; IGLESIAS AA; ARIAS DG

Rosario

Congreso; Reunicón de SAIB (50 reunión); 2014

Glutaredoxins (Grx) are small proteins linked to the cellular iron and redox metabolism. Trypanosoma cruzi is the protozoan parasite that causes the Chagas disease. Despite a putative monothiolic glutaredoxin (TcrPICOT80) is encoded in the genome of T. cruzi, it was not yet characterized. In this work, we present the functional and structural properties of the recombinant TcrPICOT80. The protein was able to catalyze the in vitro reduction of GSSG using T(SH)2 as electron donor. In addition, the protein was subjected to in vitro iron-sulfur cluster (ISC) reconstitution and the resultant absorption spectra revealed two characteristic peaks (at 320 and 420 nm) of ISC-Grx complexes. Furthermore, gel filtration chromatography profile indicated that the ISC‑Grx complex eluted with retention volume nearly corresponding to that expected for dimeric Grx specie. On the other hand, we employed a yeast-based functional complementation assay to rescue phenotypes of Grx mutants. The complementation experiments demonstrate that Dgrx5 and Dgrx4Dgrx5 can rescue phenotype in SD medium and suppressed the sensitivity of Dgrx5 cells to oxidants. These results suggest that TcrPICOT80 may have important functions in redox metabolism and the biogenesis of ISC in T. cruzi.