Quantification of Surface Tension Effects and Nucleation-and-Growth Rates during Self-Assembly of Biological Condensates
Abstrakt
Liquid-solid and liquid-liquid phase separation (PS) drives the formation offunctional and disease-associated biological assemblies. Principles of phaseequilibrium are here employed to derive a general kinetic solution thatpredicts the evolution of the mass and size of biological assemblies.Thermodynamically, protein PS is determined by two measurableconcentration limits: the saturation concentration and the critical solubility.Due to surface tension effects, the critical solubility can be higher than thesaturation concentration for small, curved nuclei. Kinetically, PS ischaracterized by the primary nucleation rate constant and a combined rateconstant accounting for growth and secondary nucleation. It is demonstratedthat the formation of a limited number of large condensates is possiblewithout active mechanisms of size control and in the absence of coalescencephenomena. The exact analytical solution can be used to interrogate how theelementary steps of PS are affected by candidate drugs.
