FIG. 1.

Close-up view of the anion/cation binding site in the cobalt-DtxR structure determined at a 1.85-Å resolution (17) showing the coordination of the Co²⁺ and sulfate ions in addition to the interaction between E20 in domain 1 and R80 in the anion/cation binding site of domain 2. Hydrogen bonds are depicted as dashed lines. The helices depicted in green belong to the dimerization domain, and the helix shown in violet represents the DNA binding domain of DtxR. One of the sulfate-coordinating ligands, N130, was omitted (17) to show more clearly the E20-R80 interaction.