Figure 3.

Average interaction energy J(N) per trimer (in units of coupling strength J₀) as a function of cluster size (number of trimers, N). Trimers are shown by orange disks, and trimer-trimer coupling of strength J₀ by green bars. Clusters are assumed to have a triangular lattice structure. Symbols represent small compact clusters of minimal circumference. Solid and dashed lines represent the “ring model” and “fit-to-symbols model”, respectively (see Model section). The horizontal dotted line shows the average interaction energy for an infinitely large cluster. (Inset) Possible mechanisms of trimer-trimer coupling including that mediated by receptor-bound CheA-CheW and membrane deformations based on large hydrophobic transmembrane domains.