Thiol-Dependent Peroxidases in Mycobacterium tuberculosis Antioxidant Defense

Mycothiol/Mycoredoxin 1-dependent Reduction of the Peroxiredoxin AhpE from Mycobacterium tuberculosis

“…S-Mycothiolation affected CgTPx activity that was restored by incubation with CgMrx1 (17). MSH/Mrx1-dependent reduction has not been described in other Prxs from Mycobacteria (TPx and AhpC) studied so far, where NADPH/thioredoxin reductase is directly used to reduce different isoforms of thioredoxin, the reducing substrates for most of the bacterial Prxs (13,18). For MtAhpC, an alternative reducing system, based on dihydrolipoamide linked to metabolic enzymes, has been demonstrated (42).…”

“…So far no MtMrx1-dependent protein reduction has been described in Mycobacteria. M. tuberculosis expresses a heme-dependent peroxidase (catalase peroxidase, KatG, EC 1.11.1.6) and several thiol-dependent peroxidases of the peroxiredoxin (Prx, EC 1.11.1.15) type, including alkyl hydroperoxide reductase C, TPx, two bacterioferritin comigratory proteins (Bcp andBcpB) and alkyl hydroperoxide reductase E (MtAhpE) (13,18). 7 As a one-cysteine peroxidase, MtAhpE lacks a resolving cysteine.…”