scholarly journals Large-Scale Molecular Dynamics Simulations of Homogeneous Nucleation of Pure Aluminium

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1217 ◽  
Author(s):  
Papanikolaou ◽  
Salonitis ◽  
Jolly ◽  
Frank
Keyword(s):  
Molecular Dynamics ◽  
Large Scale ◽  
Solidification Process ◽  
Md Simulations ◽  
Pure Aluminium ◽  
3 Dimensional ◽  
Hexagonal Close Packed ◽  
Simulation Domain ◽  
Dynamics Simulations ◽  
Insight Into

Despite the continuous and remarkable development of experimental techniques for the investigation of microstructures and the growth of nuclei during the solidification of metals, there are still unknown territories around this topic. The solidification in nanoscale can be effectively investigated by means of molecular dynamics (MD) simulations which can provide a deep insight into the mechanisms of the formation of nuclei and the induced crystal structures. In this study, MD simulations were performed to investigate the solidification of pure Aluminium and the effects of the cooling rate on the final properties of the solidified material. A large number of Aluminium atoms were used in order to investigate the grain growth over time and the formation of stacking faults during solidification. The number of face-centred cubic (FCC), hexagonal close-packed (HCP) and body-centred cubic (BCC) was recorded during the evolution of the process to illustrate the nanoscale mechanisms initiating solidification. The current investigation also focuses on the exothermic nature of the solidification process which has been effectively captured by means of MD simulations using 3 dimensional representations of the kinetic energy across the simulation domain.

scholarly journals Visual Analytics for Deep Embeddings of Large Scale Molecular Dynamics Simulations

2019 ◽  
Author(s):  
Junghoon Chae ◽  
Debsindhu Bhowmik ◽  
Heng Ma ◽  
Arvind Ramanathan ◽  
Chad Steed
Keyword(s):  
Molecular Dynamics ◽  
Visual Analytics ◽  
Large Scale ◽  
Physical Phenomenon ◽  
Living Organism ◽  
Md Simulations ◽  
High Dimensional ◽  
Molecular Characteristics ◽  
Complex Simulation ◽  
Dynamics Simulations

AbstractMolecular Dynamics (MD) simulation have been emerging as an excellent candidate for understanding complex atomic and molecular scale mechanism of bio-molecules that control essential bio-physical phenomenon in a living organism. But this MD technique produces large-size and long-timescale data that are inherently high-dimensional and occupies many terabytes of data. Processing this immense amount of data in a meaningful way is becoming increasingly difficult. Therefore, specific dimensionality reduction algorithm using deep learning technique has been employed here to embed the high-dimensional data in a lower-dimension latent space that still preserves the inherent molecular characteristics i.e. retains biologically meaningful information. Subsequently, the results of the embedding models are visualized for model evaluation and analysis of the extracted underlying features. However, most of the existing visualizations for embeddings have limitations in evaluating the embedding models and understanding the complex simulation data. We propose an interactive visual analytics system for embeddings of MD simulations to not only evaluate and explain an embedding model but also analyze various characteristics of the simulations. Our system enables exploration and discovery of meaningful and semantic embedding results and supports the understanding and evaluation of results by the quantitatively described features of the MD simulations (even without specific labels).

Molecular Basis Explanation of Imatinib Resistance of Bcr-Abl Due to T315I and P-Loop Mutations from Molecular Dynamics Simulations.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2917-2917
Author(s):  
Tai-Sung Lee ◽  
Steven Potts ◽  
Hagop Kantarjian ◽  
Jorge Cortes ◽  
Francis Giles ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Conformational Changes ◽  
Electrostatic Interactions ◽  
Large Scale ◽  
Resistance Mechanism ◽  
Md Simulations ◽  
Resistance Mechanisms ◽  
Static Structure ◽  
Imatinib Resistance ◽  
Dynamics Simulations

Abstract Molecular dynamics (MD) simulations on the complex of imatinib with the wild-type, T315I, and other 10 P-loop mutants of the tyrosine kinase Bcr-Abl have been performed to study the imatinib resistance mechanism at the atomic level. MD simulations show that large scale computational simulations could offer insight information that a static structure or simple homology modeling methods cannot provide for studying the Bcr-Abl imatinib resistance problem, especially in the case of conformational changes due to remote mutations. By utilizing the Molecular Mechanics/Poisson-Boltzmann surface area (MM-PBSA) techniques and analyzing the interactions between imatinib and individual residues, imatinib resistance mechanisms not previously thought have been revealed. Non-directly contacted P-loop mutations either unfavorably change the direct electrostatic interactions with imatinib, or cause the conformational changes influencing the contact energies between imatinib and other non-P-loop residues. We demonstrate that imatinib resistance of T315I mainly comes from the breakdown of the interactions between imatinib and E286 and M290, contradictory to previously suggested that the missing hydrogen bonding is the main contribution. We also demonstrate that except for the mutations of the direct contact residues, such as L248 and Y253, the unfavorable electrostatic interaction between P-loop and imatinib is the main reason for resistance for the P-loop mutations. Furthermore, in Y255H, protonation of the histidin is essential for rendering this mutation resistant to Gleevec. Our results demonstrate that MD is a powerful way to verify and predict clinical response or resistance to imatinib and other potential drugs.

scholarly journals KEAP1 Cancer Mutants: A Large-Scale Molecular Dynamics Study of Protein Stability

2021 ◽  
Vol 22 (10) ◽  
pp. 5408
Author(s):  
Carter Wilson ◽  
Megan Chang ◽  
Mikko Karttunen ◽  
Wing-Yiu Choy
Keyword(s):  
Molecular Dynamics ◽  
Large Scale ◽  
Md Simulations ◽  
Covalent Modification ◽  
Additional Insight ◽  
New Class ◽  
Kelch Domain ◽  
Cancer Mutations ◽  
Mutagenic Effects ◽  
Insight Into

We have performed 280 μs of unbiased molecular dynamics (MD) simulations to investigate the effects of 12 different cancer mutations on Kelch-like ECH-associated protein 1 (KEAP1) (G333C, G350S, G364C, G379D, R413L, R415G, A427V, G430C, R470C, R470H, R470S and G476R), one of the frequently mutated proteins in lung cancer. The aim was to provide structural insight into the effects of these mutants, including a new class of ANCHOR (additionally NRF2-complexed hypomorph) mutant variants. Our work provides additional insight into the structural dynamics of mutants that could not be analyzed experimentally, painting a more complete picture of their mutagenic effects. Notably, blade-wise analysis of the Kelch domain points to stability as a possible target of cancer in KEAP1. Interestingly, structural analysis of the R470C ANCHOR mutant, the most prevalent missense mutation in KEAP1, revealed no significant change in structural stability or NRF2 binding site dynamics, possibly indicating an covalent modification as this mutant’s mode of action.

scholarly journals Molecular dynamics simulations disclose early stages of the photo-activation of cryptochrome 4

2018 ◽  
Author(s):  
D. R. Kattnig ◽  
C. Nielsen ◽  
I. A. Solov’yov
Keyword(s):  
Molecular Dynamics ◽  
Conformational Changes ◽  
Large Scale ◽  
Conformational Dynamics ◽  
Md Simulations ◽  
Quantum Processes ◽  
Helical Segment ◽  
High Betweenness ◽  
Dynamics Simulations ◽  
Fad Binding

AbstractBirds appear to be equipped with a light-dependent, radical-pair-based magnetic compass that relies on truly quantum processes. While the identity of the sensory protein has remained speculative, cryptochrome 4 has recently been identified as the most auspicious candidate. Here, we report on allatom molecular dynamics (MD) simulations addressing the structural reorganisations that accompany the photoreduction of the flavin cofactor in a model of the European robin cryptochrome 4 (ErCry4). Extensive MD simulations reveal that the photo-activation of ErCry4 induces large-scale conformational changes on short (hundreds of nanoseconds) timescales. Specifically, the photo-reduction is accompanied with the release of the C-terminal tail, structural rearrangements in the vicinity of the FAD-binding site, and the noteworthy formation of an α-helical segment at the N-terminal part. Some of these rearrangements appear to expose potential phosphorylation sites. We describe the conformational dynamics of the protein using a graph-based approach that is informed by the adjacency of residues and the correlation of their local motions. This approach reveals densely coupled reorganisation communities, which facilitate an efficient signal transduction due to a high density of hubs. These communities are interconnected by a small number of highly important residues characterized by high betweenness centrality. The network approach clearly identifies the sites restructuring upon photoactivation, which appear as protrusions or delicate bridges in the reorganisation network. We also find that, unlike in the homologous cryptochrome from D. melanogaster, the release of the C-terminal domain does not appear to be correlated with the transposition of a histidine residue close to the FAD cofactor.

Large-Scale Molecular Dynamics Simulations of Interstitial Defect Diffusion in Silicon

2002 ◽  
Vol 731 ◽  
Author(s):  
David A. Richie ◽  
Jeongnim Kim ◽  
Richard Hennig ◽  
Kaden Hazzard ◽  
Steve Barr ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Large Scale ◽  
Materials Science ◽  
Tight Binding ◽  
Md Simulations ◽  
Binding Potential ◽  
Interstitial Defect ◽  
Long Time ◽  
Computational Materials ◽  
Dynamics Simulations

AbstractThe simulation of defect dynamics and evolution is a technologicaly relevant challenge for computational materials science. The diffusion of small defects in silicon unfolds as a sequence of structural transitions. The relative infrequency of transition events requires simulation over extremely long time scales. We simulate the diffusion of small interstitial clusters (I1, I2, I3) for a range of temperatures using large-scale molecular dynamics (MD) simulations with a realistic tight-binding potential. A total of 0.25 μ sec of simulation time is accumulated for the study. A novel real-time multiresolution analysis (RTMRA) technique extracts stable structures directly from the dynamics without structural relaxation. The discovered structures are relaxed to confirm their stability.

scholarly journals Deciphering collaborative sidechain motions in proteins during molecular dynamics simulations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bruck Taddese ◽  
Antoine Garnier ◽  
Hervé Abdi ◽  
Daniel Henrion ◽  
Marie Chabbert
Keyword(s):  
Molecular Dynamics ◽  
Large Scale ◽  
Conformational Transition ◽  
Transmembrane Helix ◽  
Principal Component ◽  
Dynamic Structure ◽  
Md Simulations ◽  
Outward Motion ◽  
Dynamics Simulations

Abstract The dynamic structure of proteins is essential for their functions and may include large conformational transitions which can be studied by molecular dynamics (MD) simulations. However, details of these transitions are difficult to automatically track. To facilitate their analysis, we developed two scores of correlation between sidechain dihedral angles. The CIRCULAR and OMES scores are computed from, respectively, dihedral angle values and rotamer distributions. As a case study, we applied our methods to an activation-like transition of the chemokine receptor CXCR4, observed during accelerated MD simulations. The principal component analysis of the correlation matrices was consistent with the networking structure of the top ranking pairs. Both scores identify a set of residues whose “collaborative” sidechain rotamerization immediately preceded or accompanied the conformational transition of CXCR4. Detailed analysis of the sequential order of these rotamerizations suggests that an allosteric mechanism, involving the outward motion of an asparagine residue in transmembrane helix 3, might be a prerequisite to the large scale conformational transition of CXCR4. This case study provides the proof-of-concept that the correlation methods developed here are valuable exploratory techniques to help decipher complex reactional pathways.

Topological connectivity analysis of accumulated radiation damage from multiple molecular dynamics recoil cascades

2012 ◽  
Vol 1475 ◽  
Author(s):  
Henry R. Foxhall ◽  
John H. Harding ◽  
Karl P. Travis
Keyword(s):  
Molecular Dynamics ◽  
Kinetic Energy ◽  
Radiation Damage ◽  
Large Scale ◽  
Structural Evolution ◽  
Md Simulations ◽  
Recoil Atom ◽  
Connectivity Analysis ◽  
Topological Connectivity ◽  
Insight Into

ABSTRACTThe results of sequential large-scale molecular dynamics (MD) simulations of radiation damage cascades in Gd2Ti2O7 and Gd2Zr2O7 are presented. Twelve alpha recoil cascades, each due to a recoil atom with 40 keV of kinetic energy, are performed in both materials and a stark contrast in behaviour observed. Topological connectivity analysis is used to analyse the structural evolution of the two systems. Our results provide important insight into accumulation of disorder in pyrochlore-structured ceramics.

scholarly journals Big Data Approach to Large Scale Molecular Dynamics Simulations: Necessity and Inevitability for Drug Design

2021 ◽  
Author(s):  
Dheeraj Chitara ◽  
Sanjeev B. S.
Keyword(s):  
Molecular Dynamics ◽  
Big Data ◽  
Drug Design ◽  
Large Scale ◽  
Md Simulations ◽  
Complete Analysis ◽  
Cloud Infrastructure ◽  
Drug Receptor ◽  
Dynamics Simulations ◽  
Available Resources

Molecular Dynamics (MD) simulations model motion of molecules in atomistic detail and aid in drug design. While simulations on large systems may require several days to complete, analysis of terabytes of data generated in the process could also be time consuming. Recent studies captured exciting and dramatic drug-receptor interactions under cell-like complex conditions. Such advances make simulations of biomolecular interactions more realistic, insightful, and informative and have potential to make drug design more realistic. However, currently available resources and techniques do not provide, in reasonable time, a comprehensive understanding of events seen in simulations. We demonstrate that big data approach results in significant speedups, and provides rapid insights into simulations performed. Advancing this improvement, we propose a scalable, self-tuning, and responsive framework based on Cloud-infrastructure to accomplish the best possible MD studies with given priorities and within available resources.

Assessing the Antimalarial Potentials of Phytochemicals: Virtual Screening, Molecular Dynamics and In-Vitro Investigations

2019 ◽  
Vol 16 (3) ◽  
pp. 291-300
Author(s):  
Saumya K. Patel ◽  
Mohd Athar ◽  
Prakash C. Jha ◽  
Vijay M. Khedkar ◽  
Yogesh Jasrai ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Structural Integrity ◽  
Md Simulations ◽  
Tylophora Indica ◽  
Multidrug Resistance Protein 1 ◽  
Receptor Complexes ◽  
Resistance Protein ◽  
Dynamics Simulations ◽  
Stable Trajectory

Background: Combined in-silico and in-vitro approaches were adopted to investigate the antiplasmodial activity of Catharanthus roseus and Tylophora indica plant extracts as well as their isolated components (vinblastine, vincristine and tylophorine). </P><P> Methods: We employed molecular docking to prioritize phytochemicals from a library of 26 compounds against Plasmodium falciparum multidrug-resistance protein 1 (PfMDR1). Furthermore, Molecular Dynamics (MD) simulations were performed for a duration of 10 ns to estimate the dynamical structural integrity of ligand-receptor complexes. </P><P> Results: The retrieved bioactive compounds viz. tylophorine, vinblastin and vincristine were found to exhibit significant interacting behaviour; as validated by in-vitro studies on chloroquine sensitive (3D7) as well as chloroquine resistant (RKL9) strain. Moreover, they also displayed stable trajectory (RMSD, RMSF) and molecular properties with consistent interaction profile in molecular dynamics simulations. </P><P> Conclusion: We anticipate that the retrieved phytochemicals can serve as the potential hits and presented findings would be helpful for the designing of malarial therapeutics.

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