Mycobacterium tuberculosis Thioredoxin Reductase Is Essential for Thiol Redox Homeostasis but Plays a Minor Role in Antioxidant Defense
Fig 4
TrxB2 protects Mtb from thiol-specific oxidizing stress and contributes less to defense against oxidative and nitrosative stress.
(A and B) Susceptibility of partially TrxB2-depleted Mtb to plumbagin (A) and H2O2 (B). TrxB2-TetON-tetO-1C was cultured in 7H9 medium without atc for 3 days to decrease TrxB2 expression before treatment with plumbagin and H2O2. OD580 was recorded and normalized to the corresponding strains without drug treatment. (C) Survival of Mtb strains after 4 days exposure to increasing concentrations of NaNO2 at pH 5.5. Data are means ± SD (n = 3 per group) and are representative of two independent experiments. (* p<0.05, one way ANOVA was used for group comparison). (D) Susceptibility of partially TrxB2-depleted Mtb to diamide. (E) Impact of dithiothreitol (DTT) on TrxB2 depletion-induced death in the TrxB2-DUC strain. *p<0.05, **p<0.01 and ***p<0.001 by unpaired Student’s t test. (F) Impact of extracellular glutathione (GSH) and catalase on TrxB2 depletion-induced death in the TrxB2-DUC strain. Data shown means ± SD (n = 3 per group) and are representative of two to three independent experiments.