Bridging induced coil-to-globule transition and aggregation of polymers [HBNI Th267]

Abstract

Macromolecules or polymers are generally found in crowded environments. The interior of a cell contains a high concentration of macromolecules, typically constituting 20–30% of the total cell volume. Crowders play a crucial role in the coil-to-globule (C-G) transition of macromolecules, which is essential for the functioning of biomacromolecules such as RNA, DNA, and proteins. The C-G transition can occur due to various factors, including solvent quality, co-non-solvency, temperature-mediated changes, depletion effects, and more. The C-G transition induced by bridging interactions, where crowders act as bridges or glues between monomers to facilitate polymer collapse, is discussed. Extensive coarse-grained molecular dynamics simulations are performed to investigate the phase diagram of both neutral and charged polymers in the presence of attractive crowders. Additionally, the effects of crowder-crowder interactions, density, counterion valency, and crowder size on these transitions are explored. The C-G transition in a mixture of solvent and cosolvent driven by solvent-cosolvent attraction, a phenomenon similar to cononsolvency, is also examined. Finally, polymer aggregation in the presence of attractive crowders is briefly addressed.