FIGURE 1.

Electron density maps of the ADP–AlF₃ binding site. (A) Stereo view of a SIGMAA weighted 3F_o−2F_c electron density map contoured at 1.3 σ. (B–D) F_o−F_c omit maps, using simulated annealing started at 2000 K, contoured at 3.5 σ of either (B) the ADP–AlF₃ and Mg²⁺ with its three coordinating waters omitted. (C) Lys88 and a nearby water molecule (w_n) omitted. (D) motif I (also known as the P-loop or Walker A motif) omitted. (E) Coordination of AlF₃ with selected side chains, ADP, and the catalytic water (w_c), the relay water (w_r), w_n and three Mg²⁺ coordinating waters. All densities are displayed on top of complex I. Carbon atoms are colored gray, nitrogen atoms blue, phosphorous atoms wheat, and oxygen atoms red. The magnesium ion is shown in gray as a sphere that is larger than the red water molecules. The AlF₃ is colored as the phosphates. This color scheme is used in all figures.