Square-well fluid modelling of protein liquid-vapor coexistence.

The liquid-vapor phase diagrams for square-well fluid with extremely short attractive well, lambda=1.05 and 1.1, are obtained by means of canonical Monte Carlo simulations. These new results show that the coexistence curves obey the law of corresponding states in the similar form as several proteins do. Besides, the critical packing fraction of gamma-crystalline obtained experimentally is surprisingly close to the critical value of the model fluid with lambda=1.1. Thus, we demonstrate that the phase behavior of protein solutions may be modeled without taking into account an implicit anisotropic patchy character of the interprotein interaction.