Generation of a dyad symmetric MrtR-binding site in PvirB increased the affinity and stability of the VjbR-DNA complex. (A) Schematic representation of sequences corresponding to wild-type probe PvirB, probe PvirB-MrtR bs, or the mrtI promoter (PmrtI) of M. tianshanense. Sequences that match the MrtR-binding site of PmrtI are highlighted in gray. The dyad symmetry of the MrtR-binding site is indicated by arrows. (B) DNase I footprinting analysis performed with probe PvirB-MrtR bs and increasing concentrations of VjbR, as indicated. The VjbR-protected region is indicated by an open rectangle. Arrowheads indicate DNase I hypersensitivity sites. (C) EMSA performed with a control probe, probe PvirB, or probe PvirB-MrtR bs and increasing concentrations of VjbR.