Sequential binding-unbinding based specific interactions influence exchange dynamics and size distribution of protein condensates

The interaction lifetimes between condensate-forming biomolecules can dictate both the specificity of the condensate-forming species as well as the fluidity and exchange dynamics of these condensates. Using a heuristic modeling approach, we show that single-step vs. sequential, multistep binding-unbinding interactions between proteins can lead to similar average interaction lifetimes, but with either exponential or truncated power-law-like lifetime distributions, respectively. Combining this model with Brownian dynamics simulations, we find that the differences in these lifetime distributions influence the features of condensates, such as their fluidic nature, aging, and size distribution.