Oxidoreductase activity and iron-sulfur cluster binding of glutaredoxins from Leptospira interrogans

SASONI, NATALIA; GUERRERO, SERGIO A.; IGLESIAS, ALBERTO A.; ARIAS, DIEGO G.

Córdoba

Congreso; SAIB LII Reunión anual; 2016

SAIB

Glutaredoxins are small and ubiquitous GSH-dependent oxidoreductases. The classification based on the active site motif and catalytic cycle include two groups; monothiol (1CGrx) and dithiol (2CGrx) Grx. In general, 2CGrxs are able to reduce protein disulfide, while the 1CGrxs are involved in iron homeostasis. The Leptospira interrogans genome project presents encoding genes for putative 1CGrx and 2CGrx. In this work, we present functional and structural properties of the recombinants proteins. Lin2CGrx (but not Lin1CGrx) was able to reduce in vitroLinMsrB (methionine sulfoxide reductase B) dehydroascorbate and HEDS (2-Hydroxyethyl disulfide).On the other hand, gel filtration chromatography and UV-Vis spectroscopy experiments indicated that Lin1CGrx isolated from the recombinant E. coli cells is a Fe-S cluster binding protein. This holo-protein has homodimer structure and the absorption spectra revealed that the Fe-S cluster had two characteristic peaks at 320 and 420 nm. In addition, the yeast functional complementation experiments demonstrated that Lin1CGrx can rescue the phenotype of mutants lacking Grx5, which are partially deficient in growth in SD and YPD media and also highly sensitive to oxidative stress. These results suggest that L. interrogans Grxs have important functions in redox and iron metabolism.