Figure 3.

Sliding–rebinding model for selectin–ligand interactions. The interdomain hinge is represented as a coiled spring. The yellow arrows indicate possible sequences of events. On the top left, a ligand binds to a selectin with a closed interdomain angle. A low applied force (f, short arrow) perpendicular to the binding interface favors ligand dissociation (bottom left). As applied force increases (f, long arrow), the equilibrium between the closed- and open-angle conformations shifts in favor of the open conformation (top right). This tilts the interface to align with the force direction, allowing the ligand to slide across the interface. Sliding allows new interactions to form or the original interactions to reform (rebinding). Eventually both old and new interactions break, and the ligand dissociates (bottom right).