scholarly journals Deformation and rupture of vesicles confined in narrow channels

2017 ◽  
Vol 95 (10) ◽  
pp. 916-922 ◽  
Author(s):  
Alison Harman ◽  
Martine Bertrand ◽  
Béla Joós

Using coarse-grained molecular dynamics simulations, we investigate the rheological properties of lipid bilayer vesicles as they travel in tight capillaries, such as those found in the vasculature and micro-fluidic devices. By varying the channel size, we study the build-up of tension as the flow increases with the aim of predicting the location of lysis and the mechanisms of rupture. Highly confined, fully inflated vesicles show the greatest stress and rupture near their front tip. We also simulate vesicles with reduced volume v = 0.6, the same reduced volume as red blood cells, to show how stress builds up in those objects in various conditions.

2020 ◽  
Author(s):  
Florencia Klein ◽  
Daniela Cáceres-Rojas ◽  
Monica Carrasco ◽  
Juan Carlos Tapia ◽  
Julio Caballero ◽  
...  

<p>Although molecular dynamics simulations allow for the study of interactions among virtually all biomolecular entities, metal ions still pose significant challenges to achieve an accurate structural and dynamical description of many biological assemblies. This is particularly the case for coarse-grained (CG) models. Although the reduced computational cost of CG methods often makes them the technique of choice for the study of large biomolecular systems, the parameterization of metal ions is still very crude or simply not available for the vast majority of CG- force fields. Here, we show that incorporating statistical data retrieved from the Protein Data Bank (PDB) to set specific Lennard-Jones interactions can produce structurally accurate CG molecular dynamics simulations. Using this simple approach, we provide a set of interaction parameters for Calcium, Magnesium, and Zinc ions, which cover more than 80% of the metal-bound structures reported on the PDB. Simulations performed using the SIRAH force field on several proteins and DNA systems show that using the present approach it is possible to obtain non-bonded interaction parameters that obviate the use of topological constraints. </p>


Author(s):  
Łukasz Piotr Baran ◽  
Wojciech Rżysko ◽  
Dariusz Tarasewicz

In this study we have performed extensive coarse-grained molecular dynamics simulations of the self-assembly of tetra-substituted molecules. We have found that such molecules are able to form a variety of...


2020 ◽  
Vol 22 (16) ◽  
pp. 8757-8767
Author(s):  
Tomasz Staszewski ◽  
Małgorzata Borówko

We use coarse-grained molecular dynamics simulations to study the behavior of polymer-tethered particles immersed in fluids of isotropic particles.


2021 ◽  
Author(s):  
Hiroki Koide ◽  
Noriyuki Kodera ◽  
Shveta Bisht ◽  
Shoji Takada ◽  
Tsuyoshi Terakawa

The condensin protein complex compacts chromatin during mitosis using its DNA-loop extrusion activity. Previous studies proposed scrunching and loop-capture models as molecular mechanisms for the loop extrusion process, both of which assume the binding of double-strand (ds) DNA to the so-called hinge domain formed at the interface of the condensin subunits Smc2 and Smc4. However, how the hinge domain contacts dsDNA has remained unknown, potentially due to its conformational plasticity. Here, we conducted atomic force microscopy imaging of the budding yeast condensin holo-complex and used this data as basis for coarse-grained molecular dynamics simulations to model the hinge structure in a transient open conformation. We then simulated the dsDNA binding to open and closed hinge conformations, predicting that dsDNA binds to the outside surface when closed and to the outside and inside surfaces when open. Our simulations also suggested that the hinge can close around dsDNA bound to the inside surface. The conformational change of the hinge domain might be essential for the dsDNA binding regulation and play important roles in condensin-mediated DNA-loop extrusion.


Soft Matter ◽  
2021 ◽  
Author(s):  
Rakesh K Vaiwala ◽  
Ganapathy Ayappa

A coarse-grained force field for molecular dynamics simulations of native structures of proteins in a dissipative particle dynamics (DPD) framework is developed. The parameters for bonded interactions are derived by...


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