Fig. 5

Allosteric modulators can exacerbate the hook effect by reducing cooperativity. As in the previous figure, we show fully bound calmodulin as a function of initial calmodulin concentration, both for wildtype calmodulin (black) and an in silico mutant that exists only in the R state (red). We also show the results of adding two concentrations of the allosteric activator CaMKII (blue). a At 140 μ M CaMKII, calmodulin exists almost exclusively in the R state and thus behaves like the non-cooperative in silico mutant. b at 1 μ M CaMKII, both states exist and the prozone effect is comparable to wildtype calmodulin