Figure 2 - full size

 

Figure 2.
Figure 2. Structure of T7 RNAP EC with Bound AMPcPPThe protein structure is shown by ribbon diagram. The refolded N-terminal domain and the rest of the protein are cyan and white, respectively. RNA, DNA template, and nontemplate nucleotides are shown in yellow, red, and blue, respectively. AMPcPP (green sticks) and protein side chains (white sticks) involved in a substrate binding are shown by ball-and-stick models. Mg^2+ ions are shown as magenta spheres.(A) Simulated annealing |Fobs − Fcalc| omit electron density maps produced after refinement for substrate (green, 3σ level) and Mg^2+ ions (blue, 5σ level).(B) Overall view of the T7 RNAP EC with AMPcPP bound in the substrate entry channel along the open O helix.(C) Substrate binding site. Hydrogen bonds and Mg^2+ coordination bonds are shown as white dashed sticks.

The above figure is reprinted by permission from Cell Press: Cell (2004, 116, 381-391) copyright 2004.