  Liquid-liquid phase separation of charge/aromatic-enriched intrinsically
disordered proteins (IDPs) is critical in the biological function of
membraneless organelles. Much of the physics of this recent discovery remains
to be elucidated. Here we present a theory in the random phase approximation to
account for electrostatic effects in polyampholyte phase separations, yielding
predictions consistent with recent experiments on the IDP Ddx4. The theory is
applicable to any charge pattern and thus provides a general analytical
framework for studying sequence dependence of IDP phase separation.
