Fig. 2.

(A) Secreted protein, Rv0203, and membrane protein, MmpL11, facilitate heme uptake. MtbΔmbtB, MtbΔmbtBΔRv0203, and MtbΔmbtBΔmmpL11 were grown in 7H9–0.01% tyloxapol media containing mycobactin J (myc) (10 ng/mL), 0.4 μM heme (0.4 μM Hm), 0.2 μM human hemoglobin (0.2 μM Hb), or no added supplement (No Sup.). Growth was determined by measuring absorbance at 750 nm. Experiments were performed three to five times with similar results. (B) Complementation analysis of MtbΔmbtBΔRv0203 and MtbΔmbtBΔmmpL11 in studies in which the noncomplemented strains contain the control plasmid pNBV1. Growth and measurement conditions were the same as in A although the medium contained 50 μg/mL hygromycin. Three independent experiments were performed, and growth was compared as described in Table 1. The data are displayed as percentage of growth (mean ± SE) relative to MtbΔmbtB pNBV1.