Figure 2.

Structure of MepR. (A) Ribbon diagram of the MepR subunit. The secondary structural elements are labelled and rainbow colored from red (N-terminus) to blue (C-terminus). The N- and C-termini are indicated as N and C, respectively. With the exception of the loops between β1 and β2, all loops are colored grey. (B) Ribbon diagram of the MepR dimer. The secondary structure elements of one subunit is color coded as in Figure 2A. The dyadic mate is colored magenta. The dimerization interface and the winged helix-turn-helix motif (wHTH) are labelled. (C) Primary sequence alignment of MepR with other structurally characterized MarR family members [MepR, B. subtilis OhrR (OhrR-B), X. campestris OhrR (OhrR-X), E. coli MarR, P. aeruginosa MexR and Methanobacterium MarR, MTH313]. The multiple sequence alignment was made with ClustalW (45). The secondary structure elements of MepR are indicated above the alignment, α helices as rectangles and β strands as arrows, and colored as in Figure 2A. Identical residues are colored red and the chemically similar residues are blue. The conserved hydrophobic residues that are involved in dimerization are highlighted in shaded boxes. The magenta asterisks (*) indicate the positions of MepR mutations that had been identified from clinically isolated or in vitro selected multidrug-resistant strains of S. aureus.