Fig. 4

The PefCD transporter protects GAS from heme-mediated lipid oxidation. Cultures of NZ131 (WT), ZE4951 (Mutant), ZE4951/pANKITA5b (Complement), and ZE4951/pKSM201 (Empty vector) strains were treated with 1 μM heme during the mid logarithmic phase of growth (60–70 Klett units). Culture samples were then collected at 30, 60, and 90 min post-heme exposure and allowed to react with TBA. The sample absorption at 532 nm was determined, and the formation of TBA-reactive-substances (TBARS) was calculated using the standard curve shown in A. All samples were standardized with respect to cell number. The data are derived from two independent experiments, each done in triplicates. The asterisk (*) denotes that the observed P value is statistically significant (P < 0.05) calculated using student t-test (equal variance) at 0.05 levels of significance