Fig. 3.

Simulated phase behaviors of Ddx4 IDR variants in a hydrophobicity-dominant potential augmented by cation–$\pi$ interactions. (A) Sequence patterns of the WT and its charge-scrambled (CS), Phe to Ala (FtoA) and Arg to Lys (RtoK) variants. Select residue types are highlighted: Ala (orange), Asp and Glu (red), Phe (magenta), Lys (cyan), and Arg (dark blue); other residue types are not distinguished. (B) Simulated phase diagrams of WT, CS, FtoA, and RtoK Ddx4 IDR at various relative permittivities (${ϵ}_{\mathrm{r}}$) as indicated, using the HPS model only (Left) and the HPS model augmented with cation–$\pi$ interactions (Right) with either (Top) a uniform ${\left({ϵ}_{\mathrm{c}\pi }\right)}_{ij}$ as described in Fig. 2A or (Bottom) different ${\left({ϵ}_{\mathrm{c}\pi }\right)}_{ij}$ values for Arg and Lys as given in Fig. 2B.