FIG. 7.

WhmD structure is sensitive to treatment by a reducing agent. (A) Coomassie staining of purified WhmD (left) or WhmD C67A (right) electrophoresed on a 12% denaturing PAGE gel in the absence (lane 1) and presence (lane 2) of β-mercaptoethanol (β-ME). M, molecular mass markers (kDa). (B) Schematic representation of the effect of the reducing agent on WhmD conformation. Cysteine residues are denoted C, and M is the metal ion. Mobilities of predicted conformations 1 and 2 are indicated in panel A. (C) WhmD contains bound iron. Coomassie blue (left) and Fe-specific (right) staining of WhmD following native gel electrophoresis is shown. Oligomeric forms of WhmD are indicated by the arrowheads.