FIGURE 6.

Cartoon showing how the swapping and shifting of cross-bridging and decorating aldolase tetramers results in a change of spacings between pairs of aldolase tetramers. The decorating aldolase is shown as shaded; the cross-bridging aldolase is unshaded. The figures on the left contain the same set of starting positions of each pair as expected set given the symmetry of actin. The one on the right shows the change in spacing of the cross-bridges that accompanies moving one or both of the aldolase tetramers. The restricting feature is that all cross-bridging aldolase tetramers are either 13 or 15 subunits from a neighboring cross-bridging aldolase. Note that the patterns 13-11-13 and 13-17-13 can be generated under these restrictions.