Influence of Solvent Quality on Conformations of Crowded Polymers
arXiv:1809.08090 · doi:10.1063/1.5043434
Abstract
The structure and function of polymers in confined environments, e.g., biopolymers in the cytoplasm of a cell, are strongly affected by macromolecular crowding. To explore the influence of solvent quality on conformations of crowded polymers, we model polymers as penetrable ellipsoids, whose shape fluctuations are governed by the statistics of self-avoiding walks, appropriate for a polymer in a good solvent. Within this coarse-grained model, we perform Monte Carlo simulations of mixtures of polymers and hard-nanosphere crowders, including trial changes in polymer size and shape. Penetration of polymers by crowders is incorporated via a free energy cost predicted by polymer field theory. To analyze the impact of crowding on polymer conformations in different solvents, we compute average polymer shape distributions, radius of gyration, volume, and asphericity over ranges of polymer-to-crowder size ratio and crowder volume fraction. The simulation results are accurately predicted by a free-volume theory of polymer crowding. Comparison of results for polymers in good and theta solvents indicates that excluded-volume interactions between polymer segments significantly affect crowding, especially in the limit of crowders much smaller than polymers. Our approach may help to motivate future experimental studies of polymers in crowded environments, with possible relevance for drug delivery and gene therapy.
arXiv comment12 pages, 8 figures
References in corpus (12)
- A Coarse-Grained Model for Predicting RNA Folding Thermodynamics
- Polymer depletion effects near mesoscopic particles
- Effects of macromolecular crowding on the collapse of biopolymers
- Colloid-polymer mixtures in the protein limit
- Crowding Promotes the Switch from Hairpin to Pseudoknot Conformation in Human Telomerase RNA
- New insight into cataract formation -- enhanced stability through mutual attraction
- Soft Ellipsoid Model for Gaussian Polymer Chains
- Polymer Crowding and Shape Distributions in Polymer-Nanoparticle Mixtures
- Entropic stabilization of the folded states of RNA due to macromolecular crowding
- Influence of Polymer Shape on Depletion Potentials and Crowding in Colloid-Polymer Mixtures
- Depletion-Induced Forces and Crowding in Polymer-Nanoparticle Mixtures: Role of Polymer Shape Fluctuations and Penetrability
- Crowding of Polymer Coils and Demixing in Nanoparticle-Polymer Mixtures