Figure 2.

Normalized force (F_c/R) as a function of the distance, D, between monolayers of immobilized DC-SIGNR and bilayers containing 5 mol % Man₉GlcNAc₂-DPPE. (A) The force normalized by the substrate radius F_c/R was measured as a function of distance between the ligand-containing membrane and the 6-repeat form of DC-SIGNR. The filled squares and circles represent two successive measurements at the same sample position. Samples were in buffer maintained at 21.0 ± 0.2 °C. At D_J, the surfaces jump in to contact at the separation D_C, indicated by the vertical dashed line. At D < D_C, the force increases to the equilibrium separation D_eq at F/R = 0 (vertical dashed line). At D < D_eq the force then increases more steeply due to steric repulsion between the protein and opposed membrane. (B) Normalized force curve measured with the 6-repeat variant in (A), during approach and separation. The black circles and squares are as in (A). During separation (open circles), the surfaces jump out of contact at D_Adh (right pointing arrow).