Abstract
1,6-hexanediol disrupts many phase-separated condensates in cells and in test tubes. In this study, we use a combination of microscopy, nuclear magnetic resonance (NMR) spectroscopy, molecular simulation, and biochemical assays to probe how alkanediols suppress phase separation and why certain isomers are more effective. Alkanediols of different lengths and configurations are all capable of disrupting phase separation of the RNA-binding protein Fused in Sarcoma (FUS), though potency varies depending on both geometry and hydrophobicity, which we measure directly. Alkanediols induce a shared pattern of changes to the protein chemical environment though to differing extents. Consistent with the view that alkanediols disrupt phase separation driven by hydrophobic groups, they decrease the thermal stability of a model globular protein. Conversely, 1,6-hexanediol does not disrupt charge-mediated phase separation, such as FUS RGG-RNA and poly-lysine/poly-aspartic acid condensates. All-atom simulations show that hydroxyl groups in alkanediols mediate interaction with protein backbone and polar amino acid side chains, while the aliphatic chain allows contact with hydrophobic and aromatic residues, providing a molecular picture of how amphiphilic interactions disrupt FUS phase separation.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Extensive revision with significant new experimental and simulation data on the hydrophobic contacts disrupted by hexanediols.