The Firmicutes bacteria participate extensively in virulence and pathological processes.
Enterococcus faecalis
is
a commensal microorganism; however, it is also a pathogenic bacterium mainly associated with nosocomial infections
in immunocompromised patients. Iron-sulfur [Fe-S] clusters are inorganic prosthetic groups involved in diverse
biological processes, whose in vivo formation requires several specific protein machineries.
Escherichia coli
is
one of the most frequently studied microorganisms regarding [Fe-S] cluster biogenesis and encodes the iron-sulfur
cluster and sulfur assimilation systems. In Firmicutes
species, a unique operon composed of the
sufCDSUB genes
is responsible for [Fe-S] cluster biogenesis. The aim of this study was to investigate the potential of the
E. faecalis
sufCDSUB system in the [Fe-S] cluster assembly using oxidative stress and iron depletion as adverse growth conditions.
Quantitative real-time polymerase chain reaction demonstrated, for the first time, that Gram-positive bacteria
possess an OxyR component responsive to oxidative stress conditions, as fully described for
E. coli models. Likewise,
strong expression of the
sufCDSUB genes was observed in low concentrations of hydrogen peroxide, indicating that
the lowest concentration of oxygen free radicals inside cells, known to be highly damaging to [Fe-S] clusters, is sufficient
to trigger the transcriptional machinery for prompt replacement of [Fe-S] clusters.
