FIGURE 6.

ADP modeled in the ATP-grasp fold of truncated human ATP-citrate lyase. A, a ribbon diagram of the ATP-grasp fold of truncated human ATP-citrate lyase is shown in green. Mg²⁺-ADP is shown as a stick model with a purple ball for the ion. The stick model is colored according to atom type with phosphorus in light green, oxygen in red, nitrogen in blue, and carbon in gray. A single α-helix and three β-strands at the junction of the two domains of the ATP-grasp fold in E. coli succinyl-CoA synthetase are shown in red. B, enlarged view of the ADP-binding site of human ATP-citrate lyase. The coloring is the same as in A, except that side chains of human ATP-citrate lyase that lie near Mg²⁺-ADP are drawn with green for the carbon atoms and the carbon atoms of ADP are cyan.