Figure 4.

Docking efficiency measured for NAv-coated SUVs. (A) Concentration measurement of single diffusing SUVs. The C_V-values were 44.1 ± 0.1 nM (red line) and 29.8 ± 0.1 nM (green line). Black lines indicate a linear fit to the data. (B) Direct extraction of docking efficiency (P_D) by a global maximum-likelihood fit to the complete set of experiments performed with SUVs displaying 2.0 mol % (red line) or 10 mol % (green line) DOPE-biotin in the membrane. From Eq. 15 we found P_D = (2.2 ± 0.6) × 10⁻⁵ and P_D = (4.4 ± 0.5) × 10⁻⁵ for 2 mol % and 10 mol % DOPE-biotin, respectively. (C) Confocal fluorescence micrograph sequence displaying DiD-C₁₈-stained diffusing biotinylated SUVs docking onto an SLB presenting NAv. Red circles indicate diffusing SUVs probing the SLB interface, and the green circle identifies a successfully docked vesicle. Scale bar is 5.0 μm. (D) Distribution of SUV docking attempts (N_DIF) experienced by the SLB resolved as a function of vesicle radius R. The inset shows the number of diffusing SUVs for two different experiments with [Na⁺] = 80 mM (red) and [Na⁺] = 120 mM (green) corresponding to ${\overline{C}}_V$ = 0.10 nM and ${\overline{C}}_V$ = 0.21 nM, respectively. (E) The size distribution of all SUVs that successfully docked after t = 358 s normalized by the average bulk concentration of SUVs (${\overline{C}}_V$) for direct comparison among experiments. Docking reactions took place in buffers with [Na⁺] = 80 mM (green) and [Na⁺] = 120 mM (red).