Fig. 7
Comparative analysis of cooperative versus non-cooperative Ca2+ binding to CaM. Two mathematical models for Ca2+-Cam interactions are compared under the assumptions for the presence and absence of cooperative binding. The comparison between the two scenarios was performed under steady state conditions (a), (b) and in response to a step change in Ca2+ concentration (c), (d). The model predicts that the cooperativity influences the maximums of the concentrations for the intermediate forms (N 1/L T , N 2/L T and N 3/L T ) as well as the steady-state levels of apo- (N 0/L T ) and fully saturated forms (N 4/L T ). However, the difference observed in the distribution of the conformation species in the presence and absence of the cooperative binding is quantitative while the overall shape of the distributions remains unchanged. Due to this finding the following model analysis was performed without cooperative binding assumptions