Fig. 3

Permeability of RGG-RGG droplets to small molecules and macromolecules. a Schematic illustrating permeability of protein droplets to exogenous molecules: a molecule (red) diffusing in solution may become enriched in the droplet phase (left), partition equally between the two phases (middle), or be excluded from the droplets (right). b Rhodamine enriches in the droplets, whereas rhodamine-labeled dextrans exhibit size-dependent partitioning—larger molecules permeate the protein droplets less than smaller ones. Dextran 4.4 kDa enriches, while 10 kDa modestly enriches, and 70 kDa is largely excluded. c Partitioning of folded proteins into RGG-RGG droplets. None are strongly enriched and some are partially excluded from the RGG-RGG droplet phase. Intensity scale is the same for all micrographs. Scale bars: 10 µm