FIG 1.
Expression of the pmtA gene, encoding a P1B-4-type ATPase, is upregulated during GAS growth in the presence of excess iron. (A) Schematic representation of the topology and domain architecture of the P1B-4-type ATPase. The predicted six transmembrane helices are labeled. The amino and carboxy termini are marked with N and C, respectively. The cytosolic actuator (A) and the phosphorylation/nucleotide-binding (P-/N-) domains are indicated. The transmembrane metal-binding residues within the transmembrane 4 (TM4) and TM6 helices that are conserved among members of the P1B-4 subgroup of the P1 family of ATPases are shown. (B) Amino acid sequence alignment of the predicted TM4 and TM6 helices from PmtA of GAS and its paralogs FrvA of L. monocytogenes (Lmo) and PfeT of B. subtilis (Bsu). The conserved metal-binding residues are shaded and boxed. (C) Transcript levels of pmtA in GAS grown in THY-C medium supplemented with increasing concentrations of Fe(II) compared to GAS grown in unsupplemented medium measured by qRT-PCR. (D) Transcript levels of pmtA in GAS grown in THY-C medium supplemented with different metals compared to the untreated sample measured by qRT-PCR. Three biological replicates were performed and analyzed in triplicate. Data graphed are means ± standard deviations. Average values for unsupplemented samples were used as a reference, and fold changes in transcript levels of the indicated strains relative to the reference sample are shown.