FIG. 2.

MD simulations reveal the importance of stoichiometry to the dynamical properties of the condensate. (a) MD model for the multivalent associative proteins. Colored spheres represent $A$ and $B$ domains. (b) Representative snapshot of the dense, network-forming liquid condensate. (c) Bond relaxation time (see text) as a function of stoichiometry for different binding strengths. Symbols indicate MD simulations; solid curves indicate theory [Eq. (1)] with $c_{AB}$ estimated assuming full binding of the minority domains and with fitted values $v_{\text{cage}}=11.4,\mathrm{ }{v}_0=0.4$, and ${\tau }_0=0.37$. (d) Bond relaxation time ${\tau }_{\text{rel}}$ as a function of binding strength is consistent with predicted scaling for both equal and unequal stoichiometries [Eq. (1), Fig. 1(g)]. (e) Mean squared displacement (MSD) of individual domains as a function of time reveals diffusive scaling (dashed line) at long times (here $\delta =0$). (f) Diffusion coefficient of the minority species as a function of binding strength at equal and unequal stoichiometry. (g) Longtime diffusion coefficient plotted against bond relaxation time, for all values of $\delta$ and $\mathrm{\Delta }F$. The dotted black line indicates $D\propto {\tau }_{\mathrm{r}\mathrm{e}\mathrm{l}}^{-1}$. Transparent circles correspond to systems where one component is in large excess, $\left|\delta \right|>0.2c_{\text{tot}}$. (h) Viscosity, obtained using the Green-Kubo relation, as a function of binding strength, reflects the scaling of the bond relaxation time (d).