Figure 1

Fraction of bound proteins (Poisson initial state). A dose-response curve (the fraction of the bound proteins φ plotted as a function of a) for a Poisson-like ensemble: $〈L_0^2〉$ = ⟨L₀⟩² + ⟨L₀⟩ and $〈P_0^2〉$ = ⟨P₀⟩² + ⟨P₀⟩. Each curve is obtained by varying ⟨L₀⟩ for a fixed value of ⟨P₀⟩. The thickest full line is the reference Hill curve φ _H (a), plotted with K = 1, depicting the mean field limit. The shape of the curve does not depend on the values of the ensemble parameters ⟨L₀⟩ and ⟨P₀⟩. The thin curves are fluctuation-corrected dose-response graphs obtained using the PARNES method. The full line was obtained with ⟨P₀⟩ = 1, the dashed line with ⟨P₀⟩ = 2, and the dotted line with ⟨P₀⟩ = 4. The curves that account for noise (thinner curves) approach the reference mean field curve from below for large values of ⟨P₀⟩ but are distinct otherwise.