Figure 5.

Tuning the surface density of P-selectin receptors through the surface density of b-ZZ adapter protein. (A) Schematic drawing of the surface functionalization: ① SLB formation, ② streptavidin monolayer formation, ③ co-adsorption of b-ZZ and biotin, and ④ P-selectin-Fc anchorage. (B) AMD of P-selectin over time, determined by SE for a range of fractional b-ZZ surface coverages (as indicated). Conditions: P-selectin-Fc (67 nM) was incubated at 0 min; the start of rinses with working buffer is indicated by arrowheads in matching colors. (C) AMD of P-selectin at saturation or after 2 h of incubation (derived from B) as a function of the measured b-ZZ surface density (taken from Figure 3C). Error bars along both axes are about the size of the symbols and represent temporal noise and the effects of confidence intervals and parameter correlations when fitting the SE data for b-ZZ and P-selectin-Fc binding, respectively. Black dashed line is a linear fit through the data for Γ_b-ZZ,sat ≤ 1.5 pmol/cm².