FIGURE 2.

The values of allowed complex size N = 3N_a (upper shaded region) and the corresponding values of affinity variation R_K (lower shaded region) for different values of C ≥ 0.01 as determined by fitting the adaptive allosteric model to the response data of adding attractant from Sourjik and Berg (9). As C increases, the size of the required complex and the variation of dissociation constants increase. The effects of increasing N_a and R_K variation compensate each other, e.g., for a given C, the upper (lower) boundary of the complex size labeled by solid squares (solid circles) corresponds to the lower (upper) boundary for allowed R_K labeled by open squares (open circles). An arbitrary parameter set labeled by “X” in the allowed (shaded) parameter regions is picked with C = 0.1, N_a = 10, and R_K = 6.7 (K_{I, II, III, IV} = 28.3, 31.2, 44.5, 189.7 (μM)); the kinase activity determined from the adaptive allosteric model with these parameters is shown in the inset, together with experimental data (symbols).