GPVI-CRP binding affinity and stoichiometry. (A) Normalized sedimentation velocity size distribution from a titration of 6.7 μM GPVI with CRP (1.7 to 240 μM). (Inset) Fitting the s_w values as a function of CRP concentration to a binding isotherm yields a K_d of 5 μM. (B) Normalized sedimentation velocity size distributions for 1:1, 4:1, and 8:1 GPVI/CRP mixtures (solid lines), with the free GPVI and final 1:1 complex from panel A included for comparison (dashed lines). Note that the mixtures with 4- and 8-fold molar excess of GPVI (green and yellow lines) form complexes larger than a 1:1 complex (red dashed line).