Fig. 2
From: Signaling pathways have an inherent need for noise to acquire information
Noise, output range and information in the reversible binding of molecules. a Schematic representation of reversible binding involving a receptor and a signal as examples. ka and kd correspond to the association and dissociation rate, respectively. b Acquired information, output range, and noise for receptor-ligand binding at different affinity values (Keq). The black circle and the dotted line denote the affinity at which the mutual information between signal and output is maximized. Information, noise, and output range are normalized by their respective maximal values. Further panels show the system’s behavior at c, d weak affinity (Keq = 10–5), e, f strong affinity (Keq = 10–9), and g, h intermediate affinity (Keq = 10–7; g, h). c, e, g show the temporal dynamic of the receptor-signal complexes (NRS) at three different concentrations of the signal S. d, f, h show response distributions of the number of receptor-signal complexes at these signal concentrations (see color legend at the bottom of the figure)