Self-assembly of protein superstructures by physical interactions under cytoplasm-like conditions
The structure-driven assembly of multimeric protein complexes and the formation of intracellular phase-like protein condensates have been the subject of intense research. However, the assembly of larger superstructures comprising cellular components, such as protein nanoparticles driven by general physical rather than specific biochemical interactions, remains relatively uncharacterized. Here, we use gas vesicles (GVs)—genetically encoded protein nanoparticles that form ordered intracellular clusters—as a model system to study the forces driving multiparticle assembly under cytoplasm-like conditions. Our calculations and experimental results show that the ordered assembly of GVs can be achieved by screening their mutual electrostatic repulsion with electrolytes and creating a crowding force with dissolved macromolecules. The precise balance of these forces results in different packing configurations. Biomacromolecules such as polylysine and DNA are capable of driving GV clustering. These results provide basic insights into how physically driven interactions affect the formation of protein superstructures, offer guidance for manipulating nanoparticle assembly in cellular environments through synthetic biology methods, and inform research on the biotechnology applications of GVs.
© 2021 Biophysical Society. Received 24 February 2021, Accepted 13 May 2021, Available online 20 May 2021. The authors thank Zhen-Gang Wang and Julia Kornfield for helpful discussions. This research was supported by the National Institutes of Health (grant R01-EB018975). Related research in the Shapiro Laboratory is also supported by the Heritage Medical Research Institute, the Pew Scholarship in the Biomedical Sciences, the Packard Fellowship for Science and Engineering and the Chan Zuckerbeg Initiative. Author contributions: Y.Y. and M.G.S. conceived the study. Y.Y. and B.L. acquired the data using materials prepared by D.M. Y.Y. analyzed the data. Y.Y. and Z.J. performed the theoretical calculations. Y.Y. and M.G.S. wrote the manuscript with input from all other authors. M.G.S. supervised the research.
Supplemental Material - 1-s2.0-S0006349521004215-mmc1.pdf