FIG. 2.

DtxR and MntR recognize the putative MntR box, and binding is metal ion dependent. (A) EMSA showed that increasing concentrations of DtxR in the presence of a 125 μM concentration of either FeSO₄ (left panel) or MnCl₂ (middle panel) bound to and shifted the MntR box in a dose-dependent manner. In the absence of metal ion (right panel), no shift was seen when DtxR was added to the MntR box. (B) EMSA with MntR demonstrated that divalent cations are required for binding and shifting of the MntR box. Lane 1, S. aureus mntABC promoter/operator (P/O); lane 2, mntABC P/O (in excess) with His-tagged MntR and 0.5 mM EDTA; lane 3, mntABC P/O with His-tagged MntR; lane 4, mntABC P/O with untagged MntR and 0.5 mM EDTA; lane 5, mntABC P/O with untagged MntR.