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. Author manuscript; available in PMC: 2015 Jun 18.
Published in final edited form as: Biol Chem. 2015 May;396(5):415–444. doi: 10.1515/hsz-2015-0102

Figure 4. Proposed redox-regulation of PerRCa in the strict anaerobe Clostridium acetobutylicum by oxygen, peroxides, superoxide and functions of the PerR regulon members.

Figure 4

The PerR repressor is proposed to sense O2, O2− and H2O2 by oxidation of two His residues in the conserved regulatory Fe-binding site leading to 2-oxo-His generation. This causes PerR inactivation and derepression of the PerR regulon genes. The PerR regulon controls genes for an anaerobic oxygen and ROS detoxification pathway, including the oxygen-reducing flavodiiron proteins (fprA2), reverse rubrerythrins and peroxidases (rbr3A, rbr3B), peroxiredoxin (bcp), thiol peroxidase (tpx), glutathione peroxidase (bsa2), glutaredoxin (grx), superoxide-reducing desulfoferrodoxin (dfx), rubredoxin (rd) and the NADH-dependent rubredoxin oxidoreductase (nror). Examples for PerR regulon genes of C. acetobutylicum and their functions are also listed in Table 2.