FIGURE 1.

Structures of pol ι·DNA·nucleotide ternary complexes in the presence of Mg²⁺ or Mn²⁺. A, superposition of the overall structures of ternary complexes of pol ι(26–445) with DNA containing template G and incoming non-hydrolyzable dCMPNPP in the presence of Mg²⁺ (blue) or Mn²⁺ (red). pol ι is shown as ribbons, DNA is shown as tube and ladder, the nucleotide is shown as sticks, and metal ions are shown as spheres. B, superposition of the active sites of the pol ι(26–445)·G·dCMPNPP·Mg²⁺ (blue) and pol ι(26–445)·G·dCMPNPP·Mn²⁺ (red) complexes. Active-site residues, DNA, and nucleotide are shown as sticks, and metal ions are shown as spheres.