Consider the binding process of two soluble proteins, A and B, into a dimer

Consider the binding process of two soluble proteins, A and B, into a dimer. Assume that both proteins can be approximated as spheres. The radii of proteins A and B are RA = 22A, RB = 29A, and their diffusion coefficients are DA = 5.1 x 10-6 cm?sec-1 and DB = 3.9 x 10-6 cm?sec-1. (a) Calculate the collision rate constant of the two proteins. (b) If binding can occur at any interface between the two proteins, what is the binding (dimerization) rate constant? (c) If the dimerization domains of both proteins instead only have a surface area of 121A3, what is the binding rate constant? (d) The bound dimer complex has a diffusion coefficient of DA.B = 1.4 x 10-6cm?sec-1. Calculate the average time required for the dimer to diffuse a distance of 10 um.