FIGURE 4.

SPR analysis of LRP1-RAP binding interaction. Association and dissociation of RAP, RAP-D3, and RAP-D3 K256A/K270A to recombinant LRP1 was assessed by SPR analysis. Responses at equilibrium were plotted as a function of the analyte concentration. A, one batch of purified recombinant LRP1 was immobilized to a CM5 chip at three different ligand densities (1.3, 3.8, and 8.3 fmol/mm², respectively). Subsequently, RAP (0–2560 nm), RAP-D3 (0–800 nm), and RAP-D3 K256A/K270A (0–800 nm) were passed over the immobilized LRP1 at a flow rate of 30 μl/min. Binding to LRP1 was corrected for binding in the absence of LRP1. B, three batches of purified recombinant LRP1 were immobilized to a CM5 chip (2.5 fmol/mm²) as described above. Subsequently, RAP (0–2560 nm) was passed over the immobilized LRP1 as described above with a flow rate of 30, 60 or 90 μl/min.