Figure 3.

(A) A cartoon figure showing two views of the AAC(6′)-Ii•CoA dimer. One monomer is colored blue and the other red, with the secondary structural elements involved in the dimer interface represented by a darker shade of their respective colors. (B) This view of the AAC(6′) dimer obtained by rotating the dimer in Figure 3A ▶ by 90° about a horizontal axis passing through the center of the dimer. Elements that are in the background in (A) are now at the top of (B). The cofactors are shown as black ball-and-stick models. (C) A ball-and-stick figure depicting the interactions between the monomers of the AAC(6′) dimer. The color scheme of the panel is similar to that of (A) and (B), with the amino acid residues from one monomer colored red and those from the other colored blue. Hydrogen bonds are shown as dashed lines. Residue Phe130, a aromatic residue involved in an interdimer stacking interaction is shown in green. The partially transparent backbone atoms and cartoon β-strands indicate the position and direction of the β6 strands of the two AAC(6′)-Ii monomers.