摘要：SummaryProteomic studies have shown that cellular condensates are frequently enriched in diverse RNA molecules, which is suggestive of mechanistic links between phase separation and transcriptional activities. Here, we report a systematic experimental and computational study of thermodynamic landscapes and interfacial properties of protein-RNA condensates. We have studied the affinity of protein-RNA condensation as a function of variable RNA sequence length and RNA-protein stoichiometry under different ionic environments and external crowding. We have chosen the PolyU sequences for RNA and arginine/glycine-rich intrinsically disordered peptide (RGG) for proteins as a model system of RNA-protein condensates, which we then investigate throughin vitromicroscopy measurements and coarse-grained molecular dynamics simulations. We find that crowding and RNA chain length can have a major stabilizing effect on the condensation. We also find that the RNA-protein charge ratio is a crucial variable controlling stability, interfacial properties, and the reentrant phase behavior of RGG-RNA mixtures.Graphical abstractDisplay OmittedHighlights•LLPS with long RNAs is favored because of the lower entropic penalty of dissociation•RNA chain length modulates interfacial and material properties of condensates•Crowding can stabilize condensates with shorter RNAs•Salt reduces the reentrant LLPS window but does not change the optimal stoichiometryPhysical chemistry; Biophysical chemistry; Biophysics; Biophysical Chemistry
