Interaction between AU/VWFa-11 and the VWF A1 domain. Different concentrations of VWF/A1(1238-1481) (○), VWF/A1(1261-1468) (•), or VWF/A1(1261-1468)-R1306Q (▴, 500 nM) were perfused over a CM5-sensor chip coated with 0.06 pmol/mm² AU/VWFa-11 at a flow rate of 20 μL/min. The response at equilibrium (mol A1/mol AU/VWFa-11) was plotted against the concentration of VWF/A1 that was perfused over the chip.