Effect of Structural Variability of the Ceramide Part on the Saccharide-Ceramide Linkage in Model Glycolipids Studied by Molecular Mechanics and Molecular Dynamics Methods

1996 ◽  
Vol 61 (10) ◽  
pp. 1405-1431
Author(s):  
Zuzana Gálová ◽  
Tibor Kožár
Keyword(s):  
Molecular Dynamics ◽  
Molecular Mechanics ◽  
Energy Surface ◽  
Structural Parameters ◽  
Structural Variability ◽  
Molecular Dynamics Methods ◽  
Set Up ◽  
The Stability ◽  
Dynamics Simulations ◽  
Torsional Angles

Conformational analysis was performed for model glycosphingolipid molecules with a view to studying the effect of structural variability of the lipidic part and its flexibility on the saccharide-ceramide linkage. In addition to systematic and random molecular mechanics sampling techniques (the RAMM program), molecular dynamics simulations (Biosym DISCOVER program) were carried out to analyze the conformational energy surface of the model glycolipid molecules. The influence of the structural variability and flexibility of the lipidic part is demonstrated by prediction of the stability of different conformations around the carbohydrate-ceramide linkage. The α2, α1 and Θ1 torsional angles are the most important structural parameters with respect to the carbohydrate-ceramide connection. Two dominant conformations for the saccharide-ceramide linkage were observed, with the α2/α1/Θ1 dihedral angles in the -sc/+ac/ap and -sc/ap/-sc regions. While each of the calculation methods predicts similar flexibility in the α2/α1 space, the flexibility around the Θ1 angle differs considerably, reflecting the parametrization and set-up of the modelling protocol.

scholarly journals Molecular Docking and Dynamics Investigations for Identifying Potential Inhibitors of the 3-Chymotrypsin-like Protease of SARS-CoV-2: Repurposing of Approved Pyrimidonic Pharmaceuticals for COVID-19 Treatment

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7458
Author(s):  
Amin Osman Elzupir
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Molecular Mechanics ◽  
Surface Area ◽  
Active Sites ◽  
Inhibitory Effect ◽  
Binding Energies ◽  
Poisson Boltzmann ◽  
The Stability ◽  
Dynamics Simulations

This study demonstrates the inhibitory effect of 42 pyrimidonic pharmaceuticals (PPs) on the 3-chymotrypsin-like protease of SARS-CoV-2 (3CLpro) through molecular docking, molecular dynamics simulations, and free binding energies by means of molecular mechanics–Poisson Boltzmann surface area (MM-PBSA) and molecular mechanics–generalized Born surface area (MM-GBSA). Of these tested PPs, 11 drugs approved by the US Food and Drug Administration showed an excellent binding affinity to the catalytic residues of 3CLpro of His41 and Cys145: uracil mustard, cytarabine, floxuridine, trifluridine, stavudine, lamivudine, zalcitabine, telbivudine, tipiracil, citicoline, and uridine triacetate. Their percentage of residues involved in binding at the active sites ranged from 56 to 100, and their binding affinities were in the range from −4.6 ± 0.14 to −7.0 ± 0.19 kcal/mol. The molecular dynamics as determined by a 200 ns simulation run of solvated docked complexes confirmed the stability of PP conformations that bound to the catalytic dyad and the active sites of 3CLpro. The free energy of binding also demonstrates the stability of the PP–3CLpro complexes. Citicoline and uridine triacetate showed free binding energies of −25.53 and −7.07 kcal/mol, respectively. Therefore, I recommend that they be repurposed for the fight against COVID-19, following proper experimental and clinical validation.

Active Learning Accelerates Ab Initio Molecular Dynamics on Pericyclic Reactive Energy Surfaces

2020 ◽  
Author(s):  
Shi Jun Ang ◽  
Wujie Wang ◽  
Daniel Schwalbe-Koda ◽  
Simon Axelrod ◽  
Rafael Gomez-Bombarelli
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Transition State ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Energy Surface ◽  
Computational Cost ◽  
Reactive Trajectories ◽  
Dynamics Simulations ◽  
Energy Surfaces

<div>Modeling dynamical effects in chemical reactions, such as post-transition state bifurcation, requires <i>ab initio</i> molecular dynamics simulations due to the breakdown of simpler static models like transition state theory. However, these simulations tend to be restricted to lower-accuracy electronic structure methods and scarce sampling because of their high computational cost. Here, we report the use of statistical learning to accelerate reactive molecular dynamics simulations by combining high-throughput ab initio calculations, graph-convolution interatomic potentials and active learning. This pipeline was demonstrated on an ambimodal trispericyclic reaction involving 8,8-dicyanoheptafulvene and 6,6-dimethylfulvene. With a dataset size of approximately</div><div>31,000 M062X/def2-SVP quantum mechanical calculations, the computational cost of exploring the reactive potential energy surface was reduced by an order of magnitude. Thousands of virtually costless picosecond-long reactive trajectories suggest that post-transition state bifurcation plays a minor role for the reaction in vacuum. Furthermore, a transfer-learning strategy effectively upgraded the potential energy surface to higher</div><div>levels of theory ((SMD-)M06-2X/def2-TZVPD in vacuum and three other solvents, as well as the more accurate DLPNO-DSD-PBEP86 D3BJ/def2-TZVPD) using about 10% additional calculations for each surface. Since the larger basis set and the dynamic correlation capture intramolecular non-covalent interactions more accurately, they uncover longer lifetimes for the charge-separated intermediate on the more accurate potential energy surfaces. The character of the intermediate switches from entropic to thermodynamic upon including implicit solvation effects, with lifetimes increasing with solvent polarity. Analysis of 2,000 reactive trajectories on the chloroform PES shows a qualitative agreement with the experimentally-reported periselectivity for this reaction. This overall approach is broadly applicable and opens a door to the study of dynamical effects in larger, previously-intractable reactive systems.</div>

New molecular insights into the stability of Ni–Pd hollow nanoparticles

2017 ◽  
Vol 4 (10) ◽  
pp. 1679-1690 ◽  
Author(s):  
Hamed Akbarzadeh ◽  
Esmat Mehrjouei ◽  
Amir Nasser Shamkhali ◽  
Mohsen Abbaspour ◽  
Sirous Salemi ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Thermal Behavior ◽  
Molecular Dynamics Simulations ◽  
Structural Evolution ◽  
Hollow Nanoparticles ◽  
The Stability ◽  
Dynamics Simulations

Molecular dynamics simulations were used to investigate the structural evolution and thermal behavior of Ni–Pd hollow nanoparticles.

scholarly journals A [1 + 2] cycloaddition instead of usual [2 + 3] cycloaddition between the B12N12 cluster and methyl azide: Potential energy surface calculations and Born–Oppenheimer molecular dynamics simulations

2020 ◽  
Vol 45 ◽  
pp. 146867831990058
Author(s):  
Parvaneh Pakravan ◽  
Seyyed Amir Siadati
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Molecular Dynamics Simulations ◽  
Energy Surface ◽  
Cycloaddition Reaction ◽  
Reliable Data ◽  
Reaction Channel ◽  
Dynamics Simulations

We have examined here the possibility of functionalization of the B12N12 cluster by methyl azide by means of a [2 + 3] cycloaddition reaction in analogy with the spontaneous functionalization of C20 fullerene using the same reaction. To achieve more reliable data, all possible interactions at different positions and orientations were considered by reaction channel study and potential energy surface calculations. Also, Born–Oppenheimer molecular dynamics simulations were used to find probable species which could emerge during the reactions.

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