scholarly journals Changes in the Local Conformational States Caused by Simple Na+ and K+ Ions in Polyelectrolyte Simulations: Comparison of Seven Force Fields With and Without NBFIX and ECC Corrections

2021 ◽  
Author(s):  
Natalia Lukasheva ◽  
Dmitry Tolmachev ◽  
Hector Martinez-Seara ◽  
Mikko Karttunen
Keyword(s):  
Molecular Dynamics ◽  
Local Structure ◽  
Electrostatic Interactions ◽  
Force Fields ◽  
Water Solution ◽  
Md Simulations ◽  
Side Chain ◽  
Local Structures ◽  
Structure And Dynamics ◽  
Molecular Sizes

Electrostatic interactions have a determining role in conformational and dynamic behavior of polyelectrolyte molecules [1]. In this study, anionic polyelectrolyte molecules, poly(glutamic acid) (PGA) and poly(aspartic acid) (PASA), in water solution with the most commonly used K+ or Na+ counterions were investigated using atomistic molecular dynamics (MD) simulations. Seven common force fields, AMBER99SB-ILDN, AMBER14SB, AMBER-FB15, CHARMM22*, CHARMM27, CHARMM36m and OPLS-AA/L, both with their native parameters and with the non-bonded fix (NBFIX) and electronic continuum corrections (ECC) to were studied. These corrections have bene introduced to correct for the problem of overbinding of ions to the charged groups of polyelectrolytes. Physical properties, such as molecular sizes, local structure and dynamics, were studied using two types of common counterions, potassium and sodium. The results show that in some cases, the macroion size and dynamics depend strongly on the models (parameters) for the counterions due to strong overbinding of ions and charged side chain groups. The local structures and dynamics are more sensitive on dihedral angle parameterization resulting in a preference for defined monomer conformations amd the type of correction used.

scholarly journals Changes in the Local Conformational States Caused by Simple Na+ and K+ Ions in Polyelectrolyte Simulations: Comparison of Seven Force Fields with and without NBFIX and ECC Corrections

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 252
Author(s):  
Natalia Lukasheva ◽  
Dmitry Tolmachev ◽  
Hector Martinez-Seara ◽  
Mikko Karttunen
Keyword(s):  
Experimental Data ◽  
Electrostatic Interactions ◽  
Force Fields ◽  
Dynamic Properties ◽  
Water Solution ◽  
Md Simulations ◽  
Side Chain ◽  
Local Structures ◽  
Structure And Dynamics ◽  
Molecular Sizes

Electrostatic interactions have a determining role in the conformational and dynamic behavior of polyelectrolyte molecules. In this study, anionic polyelectrolyte molecules, poly(glutamic acid) (PGA) and poly(aspartic acid) (PASA), in a water solution with the most commonly used K+ or Na+ counterions, were investigated using atomistic molecular dynamics (MD) simulations. We performed a comparison of seven popular force fields, namely AMBER99SB-ILDN, AMBER14SB, AMBER-FB15, CHARMM22*, CHARMM27, CHARMM36m and OPLS-AA/L, both with their native parameters and using two common corrections for overbinding of ions, the non-bonded fix (NBFIX), and electronic continuum corrections (ECC). These corrections were originally introduced to correct for the often-reported problem concerning the overbinding of ions to the charged groups of polyelectrolytes. In this work, a comparison of the simulation results with existing experimental data revealed several differences between the investigated force fields. The data from these simulations and comparisons with previous experimental data were then used to determine the limitations and strengths of these force fields in the context of the structural and dynamic properties of anionic polyamino acids. Physical properties, such as molecular sizes, local structure, and dynamics, were studied using two types of common counterions, namely potassium and sodium. The results show that, in some cases, both the macroion size and dynamics depend strongly on the models (parameters) for the counterions due to strong overbinding of the ions and charged side chain groups. The local structures and dynamics are more sensitive to dihedral angle parameterization, resulting in a preference for defined monomer conformations and the type of correction used. We also provide recommendations based on the results.

scholarly journals High-resolution mining of the SARS-CoV-2 main protease conformational space: supercomputer-driven unsupervised adaptive sampling

2021 ◽  
Author(s):  
Théo Jaffrelot Inizan ◽  
Frédéric Célerse ◽  
Olivier Adjoua ◽  
Dina El Ahdab ◽  
Luc-Henri Jolly ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
High Resolution ◽  
Adaptive Sampling ◽  
Force Fields ◽  
Sampling Strategy ◽  
Md Simulations ◽  
Conformational Space ◽  
Many Body ◽  
Polarizable Force Fields ◽  
Main Protease

We provide an unsupervised adaptive sampling strategy capable of producing μs-timescale molecular dynamics (MD) simulations of large biosystems using many-body polarizable force fields (PFFs).

scholarly journals The role of side chains in the interaction of new antitumor pyrimidoacridinetriones with DNA: molecular dynamics simulations.

2000 ◽  
Vol 47 (1) ◽  
pp. 47-57 ◽  
Author(s):  
J Mazerski ◽  
I Antonini ◽  
S Martelli
Keyword(s):  
Molecular Dynamics ◽  
Rational Design ◽  
Md Simulations ◽  
Ring System ◽  
Side Chain ◽  
Side Chains ◽  
Intercalation Complex ◽  
Highly Active ◽  
Simulation Techniques ◽  
Dynamics Simulations

Pyrimidoacridinetriones (PATs) are a new group of highly active antitumor compounds. It seems reasonable to assume that, like for some other acridine derivatives, intercalation into DNA is a necessary, however not a sufficient condition for antitumor activity of these compounds. Rational design of new compounds of this chemotype requires knowledge about the structure of the intercalation complex, as well as about interactions responsible for its stability. Computer simulation techniques such as molecular dynamics (MD) may provide valuable information about these problems. The results of MD simulations performed for three rationally selected PATs are presented in this paper. The compounds differ in the number and position of side chains. Each of the compounds was simulated in two systems: i) in water, and ii) in the intercalation complex with the dodecamer duplex d(GCGCGCGCGCGC)2. The orientation of the side chain in relation to the ring system is determined by the position of its attachment. Orientation of the ring system inside the intercalation cavity depends on the number and position of side chain(s). The conformations of the side chain(s) of all PATs studied in the intercalation complex were found to be very similar to those observed in water.

scholarly journals Molecular dynamics simulations of the self-organization of side-chain decorated polyaromatic conjugation molecules: phase separated lamellar and columnar structures and dispersion behaviors in toluene solvent

RSC Advances ◽  
2018 ◽  
Vol 8 (20) ◽  
pp. 11134-11144 ◽  
Author(s):  
Lanyan He ◽  
Pingmei Wang ◽  
Lipeng He ◽  
Zhou Qu ◽  
Jianhui Luo ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Molecular Dynamic ◽  
Md Simulations ◽  
The Self ◽  
Self Organization ◽  
Side Chain ◽  
Dynamics Simulations

The self-organization of five model side-chain decorated polyaromatic asphaltene molecules with or without toluene solvent was investigated by means of molecular dynamic (MD) simulations.

scholarly journals Sorption, Structure and Dynamics of CO2 and Ethane in Silicalite at High Pressure: A Combined Monte Carlo and Molecular Dynamics Simulation Study

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 99 ◽  
Author(s):  
Siddharth Gautam ◽  
Tingting Liu ◽  
David Cole
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Time Scales ◽  
Rotational Motion ◽  
High Pressures ◽  
Sorption Isotherms ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Structure And Dynamics ◽  
Low Pressures

Silicalite is an important nanoporous material that finds applications in several industries, including gas separation and catalysis. While the sorption, structure, and dynamics of several molecules confined in the pores of silicalite have been reported, most of these studies have been restricted to low pressures. Here we report a comparative study of sorption, structure, and dynamics of CO2 and ethane in silicalite at high pressures (up to 100 bar) using a combination of Monte Carlo (MC) and molecular dynamics (MD) simulations. The behavior of the two fluids is studied in terms of the simulated sorption isotherms, the positional and orientational distribution of sorbed molecules in silicalite, and their translational diffusion, vibrational spectra, and rotational motion. Both CO2 and ethane are found to exhibit orientational ordering in silicalite pores; however, at high pressures, while CO2 prefers to reside in the channel intersections, ethane molecules reside mostly in the sinusoidal channels. While CO2 exhibits a higher self-diffusion coefficient than ethane at low pressures, at high pressures, it becomes slower than ethane. Both CO2 and ethane exhibit rotational motion at two time scales. At both time scales, the rotational motion of ethane is faster. The differences observed here in the behavior of CO2 and ethane in silicalite pores can be seen as a consequence of an interplay of the kinetic diameter of the two molecules and the quadrupole moment of CO2.

scholarly journals Structure and Dynamics of Glycosphingolipids in Lipid Bilayers: Insights from Molecular Dynamics Simulations

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Ronak Y. Patel ◽  
Petety V. Balaji
Keyword(s):  
Molecular Dynamics ◽  
Lipid Bilayers ◽  
Membrane Structure ◽  
Lipid Membrane ◽  
Biological Membranes ◽  
Md Simulations ◽  
Atomic Level ◽  
Structure And Dynamics ◽  
Hydrogen Bonding Interactions ◽  
Dynamics Simulations

Glycolipids are important constituents of biological membranes, and understanding their structure and dynamics in lipid bilayers provides insights into their physiological and pathological roles. Experimental techniques have provided details into their behavior at model and biological membranes; however, computer simulations are needed to gain atomic level insights. This paper summarizes the insights obtained from MD simulations into the conformational and orientational dynamics of glycosphingolipids and their exposure, hydration, and hydrogen-bonding interactions in membrane environment. The organization of glycosphingolipids in raft-like membranes and their modulation of lipid membrane structure are also reviewed.

Force field development and simulations of senior dialkyl sulfoxides

2016 ◽  
Vol 18 (15) ◽  
pp. 10507-10515 ◽  
Author(s):  
Vitaly V. Chaban
Keyword(s):  
Molecular Dynamics ◽  
Force Field ◽  
Ab Initio ◽  
Md Simulations ◽  
Field Development ◽  
Force Field Development ◽  
Structure And Dynamics ◽  
Ethyl Methyl ◽  
Methyl Sulfoxide ◽  
Diethyl Sulfoxide

Thermodynamics, structure, and dynamics of diethyl sulfoxide (DESO) and ethyl methyl sulfoxide (EMSO) were investigated using ab initio calculations and non-polarizable potential based molecular dynamics (MD) simulations.

scholarly journals All-atom lipid bilayer self-assembly with the AMBER and CHARMM lipid force fields

2015 ◽  
Vol 51 (21) ◽  
pp. 4402-4405 ◽  
Author(s):  
Åge A. Skjevik ◽  
Benjamin D. Madej ◽  
Callum J. Dickson ◽  
Knut Teigen ◽  
Ross C. Walker ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Lipid Bilayer ◽  
Self Assembly ◽  
Force Fields ◽  
Md Simulations ◽  
Bilayer Formation

In this work we report the first example of spontaneous lipid bilayer formation in unbiased all-atom molecular dynamics (MD) simulations.

Local structure and dynamics in AgI studied by EXAFS and molecular dynamics

1994 ◽  
Vol 69 (1) ◽  
pp. 13-19 ◽  
Author(s):  
G. Dalba ◽  
P. Fornasini ◽  
R. Gotter ◽  
S. Cozzini ◽  
M. Ronchetti ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Local Structure ◽  
Structure And Dynamics

scholarly journals Collaborative Behavior of Urea and KI in Denaturing Protein Native Structure

2019 ◽  
Author(s):  
Qiang Shao ◽  
Jinan Wang ◽  
Weiliang Zhu
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bonding ◽  
Structural Dynamics ◽  
Electrostatic Interactions ◽  
Side Chain ◽  
Mixed Solution ◽  
Native Structure ◽  
Indirect Influence ◽  
Collaborative Behavior ◽  
Dynamics Simulations

AbstractIn this work, the combined influence of urea and KI on protein native structure is quantitatively investigated through the comparative molecular dynamics simulations on the structural dynamics of a polypeptide of TRPZIP4 in a series of urea/KI mixed solutions (urea concentration: 4M, KI salt concentration: 0M-6M). The observed enhanced denaturing ability of urea/KI mixture can be explained by direct interactions of urea/K+/water towards protein (electrostatic and vdW interactions from urea and electrostatic interactions from K+ and water) and indirect influence of KI on the strengthened interaction of urea towards protein backbone and side-chain. The latter indirect influence is fulfilled through the weakening of hydrogen bonding network among urea and water by the appearance of K+–water and I—urea interactions. As a result, the denaturing ability enhancement of urea and KI mixed solution is induced by the collaborative behavior of urea and KI salt.

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