Figure 9
Proteins have surfaces that are nonsticky at the sites where they are most likely to make collisions during diffusion. (A) The effective translational diffusion over short time of points on the surface of a tumbling ellipsoid, defined by two angles θ from the a axis and φ from b, is lowest (light) at the poles of the c axis, the flattest face, and highest (dark) at the poles of the a axis. (B) Plot of the normalized distribution of collision frequency (low light to high dark) for each θφ point on the surface of a diffusing ellipsoid. (C) Plot of the frequency distribution of the location of points at the centre of the interface between monomers in a protein dimer (low light to high dark). (D) Plot of the average radial extent values (Fig. 3A) for the residues found on the surface of the monomers in protein dimers. (E) The most conserved residues on the surface of homologs are coincident with the centre of the pole at c where binding and active sites are common. (F) The a/c cross-section through the evolutionary rate data reveals that mutations of the faster-evolving residues on the surface away from the active site facilitate changes in the core.
