Fig. 2. (A) Data for binding of s-erbB1, s-erbB2, s-erbB3 and s-erbB4 to EGF (left) and NRG1-β1 (right), immobilized on a BIAcore sensor chip. Best fits to the data, assuming a simple association model, are shown. Errors are standard deviations from the mean of at least four independent determinations at each point. KD values represented by the best fits are listed in Table I. (B) Representative raw BIAcore data for s-erbB3 flowed in parallel over a biosensor chip derivatized with EGF (left) and NRG1-β1 (right) at a series of different concentrations (marked on each curve in nM).