A coarse-grained model of ionic liquid crystals: the effect of stoichiometry on the stability of the ionic nematic phase

2019 ◽  
Vol 21 (36) ◽  
pp. 20327-20337 ◽  
Author(s):  
Giacomo Saielli ◽  
Katsuhiko Satoh
Keyword(s):  
Ionic Liquid ◽  
Nematic Phase ◽  
Stoichiometric Composition ◽  
Charged Particles ◽  
Coarse Grained ◽  
Thermal Range ◽  
Coarse Grained Model ◽  
Lennard Jones ◽  
Ionic Liquid Crystals ◽  
The Stability

The thermal range of the ionic nematic phase is strongly influenced by the stoichiometric composition of the [GB]n[LJ]msalt in mixtures of Gay-Berne and Lennard-Jones charged-particles.

The effect of hydration on the stability of Ionic Liquid Crystals: MD simulations of [C14C1im]Cl and [C14C1im]Cl·H2O

2021 ◽  
Author(s):  
Giacomo Saielli
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Md Simulations ◽  
Structural Features ◽  
Thermal Range ◽  
Ionic Liquid Crystals ◽  
The Stability

The thermal range of stability of Ionic Liquid Crystals (ILC) phases of imidazolium ILCs, and the type of mesophase itself, are affected by several molecular structural features, the two prominent...

Local distortion energy and coarse-grained elasticity of the twist-bend nematic phase

Soft Matter ◽  
2016 ◽  
Vol 12 (2) ◽  
pp. 574-580 ◽  
Author(s):  
C. Meyer ◽  
I. Dozov
Keyword(s):  
Nematic Phase ◽  
Coarse Grained ◽  
Local Distortion ◽  
Coarse Grained Model ◽  
Smectic A ◽  
Smectic A Phase ◽  
Distortion Energy

We develop a coarse-grained model describing the macroscopic elasticity of the twist-bend nematic by analogy with the chiral smectic-A phase.

scholarly journals Quantitative analysis of membrane-mediated interactions and aggregation of flexible peripheral proteins orchestrating large-scale membrane remodeling

2021 ◽  
Author(s):  
Mohsen Sadeghi ◽  
Frank Noe
Keyword(s):  
Protein Interactions ◽  
Large Scale ◽  
Effective Interaction ◽  
Bilayer Membrane ◽  
Coarse Grained ◽  
Membrane Remodeling ◽  
Coarse Grained Model ◽  
Sequence Of Events ◽  
Peripheral Proteins ◽  
The Stability

Shaping and remodeling of biomembranes is essential for cellular trafficking, with membrane-binding peripheral proteins playing the key role in it. Significant membrane remodeling as in endo- and exocytosis is often due to clusters or aggregates of many proteins whose interactions may be direct or mediated via the membrane. While computer simulation could be an important tool to disentangle these interactions and understand what drives cooperative protein interactions in membrane remodeling, this has so far been extremely challenging: protein-membrane systems involve time- and lengthscales that make detailed atomistic simulations impractical, while most coarse-grained models lack the degree of detail needed to resolve the dynamics and physical effect of protein and membrane flexibility. Here, we develop a coarse-grained model of the bilayer membrane bestrewed with rotationally-symmetric flexible membrane-bound proteins. We show how this model can be parameterized based on local curvatures, protein flexibility, and the in-plane dynamics of proteins. We measure the effective interaction potential for the membrane-mediated interactions between peripheral proteins. Furthermore, we investigate the kinetics, equilibrium distributions, and the free energy landscape governing the formation and break-up of protein clusters on the surface of the membrane. We demonstrate how the flexibility of the protein plays a deciding role in highly selective macroscopic aggregation behavior. Finally, we present large-scale simulations of membrane tubulation, and discuss the sequence of events and the stability of intermediates.

scholarly journals Liquid network connectivity regulates the stability and composition of biomolecular condensates with many components

2020 ◽  
Vol 117 (24) ◽  
pp. 13238-13247 ◽  
Author(s):  
Jorge R. Espinosa ◽  
Jerelle A. Joseph ◽  
Ignacio Sanchez-Burgos ◽  
Adiran Garaizar ◽  
Daan Frenkel ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Critical Points ◽  
Network Connectivity ◽  
Coarse Grained ◽  
Physical Parameters ◽  
Protein Protein Interactions ◽  
Coarse Grained Model ◽  
Bond Network ◽  
The Stability ◽  
Liquid Liquid Phase Separation

One of the key mechanisms used by cells to control the spatiotemporal organization of their many components is the formation and dissolution of biomolecular condensates through liquid–liquid phase separation (LLPS). Using a minimal coarse-grained model that allows us to simulate thousands of interacting multivalent proteins, we investigate the physical parameters dictating the stability and composition of multicomponent biomolecular condensates. We demonstrate that the molecular connectivity of the condensed-liquid network—i.e., the number of weak attractive protein–protein interactions per unit of volume—determines the stability (e.g., in temperature, pH, salt concentration) of multicomponent condensates, where stability is positively correlated with connectivity. While the connectivity of scaffolds (biomolecules essential for LLPS) dominates the phase landscape, introduction of clients (species recruited via scaffold–client interactions) fine-tunes it by transforming the scaffold–scaffold bond network. Whereas low-valency clients that compete for scaffold–scaffold binding sites decrease connectivity and stability, those that bind to alternate scaffold sites not required for LLPS or that have higher-than-scaffold valencies form additional scaffold–client–scaffold bridges increasing stability. Proteins that establish more connections (via increased valencies, promiscuous binding, and topologies that enable multivalent interactions) support the stability of and are enriched within multicomponent condensates. Importantly, proteins that increase the connectivity of multicomponent condensates have higher critical points as pure systems or, if pure LLPS is unfeasible, as binary scaffold–client mixtures. Hence, critical points of accessible systems (i.e., with just a few components) might serve as a unified thermodynamic parameter to predict the composition of multicomponent condensates.

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