Figure 27.

Diffusion coefficients of integral membrane proteins (D) versus protein/inclusion size (R). Results are shown for a polydisperse mixture of proteins based on simulations of a coarse-grained (MARTINI) model (colored points) and a system comprised of two-dimensional disks (gray). The results are shown in dimensionless units. The lines are fits to the Saffman–Delbrück relation (full line) and the Stokes law (dotted line). (top) In the dilute case, the data fully agree with the SD model. (bottom) In the crowded case, the Stokes-like 1/R dependence of the diffusivity is evident. Different colors of the markers stand for different proteins. Adapted with permission from ref (55). Copyright 2017 American Chemical Society.