Abstract Phase separation and percolation contribute to phase transitions of multivalent macromolecules.Contributions of percolation are evident through the viscoelasticity of condensates and through the formation of heterogeneous distributions of nano- and mesoscale pre-percolation clusters in sub-saturated solutions.Here, we show that clusters formed in sub-saturated solutions Mens Belt of FET (FUS-EWSR1-TAF15) proteins are affected differently by glutamate versus chloride.
These differences on the nanoscale, gleaned using a suite of methods deployed across a wide range of protein concentrations, are prevalent and can be unmasked even though the driving forces for phase separation remain unchanged in glutamate versus chloride.Strikingly, differences in anion-mediated interactions that drive clustering saturate on the micron-scale.Beyond this length Sunglasses scale the system separates into coexisting phases.
Overall, we find that sequence-encoded interactions, mediated by solution components, make synergistic and distinct contributions to the formation of pre-percolation clusters in sub-saturated solutions, and to the driving forces for phase separation.