Figure 2. Bivalent cations and cholesterol modulate association and dissociation of Le^x-Le^x interaction.

(a) and (b) Number of newly arrived liposomes n₊ as a function of time and (c) and (d) normalized number of liposomes that are still bound as a function of time for the different buffers used: TRIS buffer without additional cations (blue), TRIS buffer containing 0.9 mM CaCl₂ and 0.5 mM MgCl₂ (red) and TRIS buffer containing 10 mM CaCl₂ (black) and the control (grey). (a) and (b) SLBs are composed of 95 wt% POPC + 5 wt% Le^x GSL and liposomes of 94 wt% POPC + 5 wt% Le^x GSL + 1wt% Rhod-PE. For the control Le^x GSL was replaced by Le^a GSL. (c) and (d) SLBs are composed of 93 wt% POPC + 5 wt% Le^x GSL + 2 wt% cholesterol and liposomes of 94 wt% POPC + 5 wt% Le^x GSL + 1 wt% Rhod-PE. Continuous lines represent the corresponding curve fits. Inset (b) and (d): Fraction of irreversible bound liposomes during the time of an experiment for (I) TRIS buffer without additional cations (blue), (II) TRIS buffer containing 0.9 mM CaCl₂ and 0.5 mM MgCl₂ (red) and (III) TRIS buffer containing 10 mM CaCl₂ (black).