The dependence of the association rate of surface-attached adhesion molecules CD2 and CD48 on separation distance.
Pierres A., Benoliel AM., Bongrand P., van der Merwe PA.
The kinetics of bond formation between spherical beads coated with CD48 and CD2-derivatized surfaces was studied with a flow chamber. For a given shear rate, the binding frequency was exquisitively sensitive to the particle velocity. Flow equations were used to derive the particle-to-surface distance from the velocity, thus yielding a relationship between this distance and the binding rate. Numerical values of the binding site densities allowed absolute determination of the rate of association between two individual molecules as a function of the distance between attachment points. In our model, this rate was about 0.03 s-1 at 10 nm separation, and it was inversely proportional to the cube of the distance.