FIGURE 7.

Snapshots of E. coli hexanoyl- and octadecanoyl-ACPs shown in A and B, respectively, taken every 50 ps over the full 20 ns of MD trajectory. C, crystal structures ranging from butyryl- to decanoyl-ACP by Roujeinikova et al. (11, 12). Panels A-C show ACP with helix IV in a transparent representation oriented toward the viewer, and gray spheres highlight the tip of the acyl chains in each structure. D, the distance of the acyl chain from the first to the last carbon group in the acyl chain of butyryl- (lower black line), hexanoyl- (dark gray), octanoyl- (light gray), decanoyl- (black), and hexadecanoyl-ACP (dotted). Notice that up to octanoyl-ACP the chain is largely extended inside the cavity, whereas beginning with decanoyl-ACP the chain is increasingly distorted, which is also reflected in panels A and B.