Stoichiometry Controls the Dynamics of Liquid Condensates of Associative Proteins

Multivalent associative proteins with strong complementary interactions play a crucial role in phase separation of intracellular liquid condensates. We study the internal dynamics of such bond-network condensates comprising two complementary proteins via scaling analysis and molecular dynamics. We find that when stoichiometry is balanced, relaxation slows down dramatically due to a scarcity of alternative binding partners following bond breakage. This microscopic slow-down strongly affects the bulk diffusivity, viscosity, and mixing, which provides a means to experimentally test this prediction.

Automated summary

Multivalent associative proteins are essential for phase separation in intracellular liquid condensates. This study investigates the internal dynamics of bond-network condensates composed of two complementary proteins through scaling analysis and molecular dynamics. The findings reveal that when the stoichiometry is balanced, relaxation significantly slows down due to a lack of alternative binding partners, which strongly influences bulk diffusivity, viscosity, and mixing. This provides an experimental means to test the prediction.