Figure 5.

Structural evidence for the proposed second metal site. Three structures of EntC are shown: (A) the low-Mg structure, as also shown in Figure 4; (B) the high-Mg structure; and (C) the re-refined 3HWO structure. The maps shown here are 2F_o – F_c maps contoured at 1.5σ. The monomer in the asymmetric unit with the best density for the loop preceding the general base lysine (yellow) is shown in shades of green. Water molecules are shown as red spheres. This site was hypothesized to bind magnesium (see Figure 3), but that could not be confirmed with any of the structures evaluated.