scholarly journals Direct Derivation of Free Energies of Membrane Deformation and Other Solvent Density Variations From Enhanced Sampling Molecular Dynamics

2019 ◽  
Vol 41 (5) ◽  
pp. 449-459 ◽  
Author(s):  
Giacomo Fiorin ◽  
Fabrizio Marinelli ◽  
José D. Faraldo‐Gómez
Keyword(s):  
Molecular Dynamics ◽  
Enhanced Sampling ◽  
Free Energies ◽  
Direct Derivation ◽  
Membrane Deformation ◽  
Solvent Density

scholarly journals Peptide Gaussian accelerated molecular dynamics (Pep-GaMD): Enhanced sampling and free energy and kinetics calculations of peptide binding

2020 ◽  
Author(s):  
Jinan Wang ◽  
Yinglong Miao
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Protein Interactions ◽  
Peptide Binding ◽  
Computational Method ◽  
Enhanced Sampling ◽  
Free Energies ◽  
Accelerated Molecular Dynamics ◽  
High Flexibility ◽  
Binding Free Energies

AbstractPeptides mediate up to 40% of known protein-protein interactions in higher eukaryotes and play an important role in cellular signaling. However, it is challenging to simulate both binding and unbinding of peptides and calculate peptide binding free energies through conventional molecular dynamics, due to long biological timescales and extremely high flexibility of the peptides. Based on the Gaussian accelerated molecular dynamics (GaMD) enhanced sampling technique, we have developed a new computational method “Pep-GaMD”, which selectively boosts essential potential energy of the peptide in order to effectively model its high flexibility. In addition, another boost potential is applied to the remaining potential energy of the entire system in a dual-boost algorithm. Pep-GaMD has been demonstrated on binding of three model peptides to the SH3 domains. Independent 1 μs dual-boost Pep-GaMD simulations have captured repetitive peptide dissociation and binding events, which enable us to calculate peptide binding thermodynamics and kinetics. The calculated binding free energies and kinetic rate constants agreed very well with available experimental data. Furthermore, the all-atom Pep-GaMD simulations have provided important insights into the mechanism of peptide binding to proteins that involves long-range electrostatic interactions and mainly conformational selection. In summary, Pep-GaMD provides a highly efficient, easy-to-use approach for unconstrained enhanced sampling and calculations of peptide binding free energies and kinetics.Significance StatementWe have developed a new computational method “Pep-GaMD” for enhanced sampling of peptide-protein interactions based on the Gaussian accelerated molecular dynamics (GaMD) technique. Pep-GaMD works by selectively boosting the essential potential energy of the peptide to effectively model its high flexibility. In addition, another boost potential can be applied to the remaining potential energy of the entire system in a dual-boost algorithm. Pep-GaMD has been demonstrated on binding of three model peptides to the SH3 domains. Dual-boost Pep-GaMD has captured repetitive peptide dissociation and binding events within significantly shorter simulation time (microsecond) than conventional molecular dynamics. Compared with previous enhanced sampling methods, Pep-GaMD is easier to use and more efficient for unconstrained enhanced sampling of peptide binding and unbinding, which provides a novel physics-based approach to calculating peptide binding free energies and kinetics.

scholarly journals Accelerating Dissociative Events in Molecular Dynamics Simulations by Selective Potential Scaling

2019 ◽  
Author(s):  
Indrajit Deb ◽  
Aaron T. Frank
Keyword(s):  
Molecular Dynamics ◽  
Sampling Method ◽  
Potential Energy Function ◽  
Md Simulations ◽  
Cyclin Dependent Kinase ◽  
Enhanced Sampling ◽  
Free Energies ◽  
Biologically Relevant ◽  
Dynamics Simulations ◽  
Dissociative Processes

ABSTRACTMolecular dynamics (or MD) simulations can be a powerful tool for modeling complex dissociative processes such as ligand unbinding. However, many biologically relevant dissociative processes occur on timescales that far exceed the timescales of typical MD simulations. Here, we implement and apply an enhanced sampling method in which specific energy terms in the potential energy function are selectively “scaled” to accelerate dissociative events during simulations. Using ligand unbinding as an example of a complex dissociative process, we selectively scaled-up ligand-water interactions in an attempt to increase the rate of ligand unbinding. By applying our selectively scaled MD (or ssMD) approach to three cyclin-dependent kinase 2 (CDK2)-inhibitor complexes, we were able to significantly accelerate ligand unbinding thereby allowing, in some cases, unbinding events to occur within as little as 2 ns. Moreover, we found that we could make realistic estimates of the unbinding as well as the binding free energies (∆Gsim) of the three inhibitors from our ssMD simulation data. To accomplish this, we employed a previously described Kramers’-based rate extrapolation (KRE) method and a newly described free energy extrapolation (FEE) method. Because our ssMD approach is general, it should find utility as an easy-to-deploy, enhanced sampling method for modeling other dissociative processes.

scholarly journals Doxorubicin Encapsulation in Carbon Nanotubes Having Haeckelite or Stone–Wales Defects as Drug Carriers: A Molecular Dynamics Approach

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1586
Author(s):  
Leonor Contreras ◽  
Ignacio Villarroel ◽  
Camila Torres ◽  
Roberto Rozas
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Drug Delivery Systems ◽  
Nitrogen Doping ◽  
Drug Carriers ◽  
Acidic Ph ◽  
Free Energies ◽  
Interaction Forces ◽  
Chiral Nanotubes ◽  
Binding Free Energies

Doxorubicin (DOX), a recognized anticancer drug, forms stable associations with carbon nanotubes (CNTs). CNTs when properly functionalized have the ability to anchor directly in cancerous tumors where the release of the drug occurs thanks to the tumor slightly acidic pH. Herein, we study the armchair and zigzag CNTs with Stone–Wales (SW) defects to rank their ability to encapsulate DOX by determining the DOX-CNT binding free energies using the MM/PBSA and MM/GBSA methods implemented in AMBER16. We investigate also the chiral CNTs with haeckelite defects. Each haeckelite defect consists of a pair of square and octagonal rings. The armchair and zigzag CNT with SW defects and chiral nanotubes with haeckelite defects predict DOX-CNT interactions that depend on the length of the nanotube, the number of present defects and nitrogen doping. Chiral nanotubes having two haeckelite defects reveal a clear dependence on the nitrogen content with DOX-CNT interaction forces decreasing in the order 0N > 4N > 8N. These results contribute to a further understanding of drug-nanotube interactions and to the design of new drug delivery systems based on CNTs.

Toward an Enhanced Sampling Molecular Dynamics Method for Studying Ligand-Induced Conformational Changes in Proteins

2015 ◽  
Vol 119 (46) ◽  
pp. 14594-14603 ◽  
Author(s):  
Ole Juul Andersen ◽  
Julie Grouleff ◽  
Perri Needham ◽  
Ross C. Walker ◽  
Frank Jensen
Keyword(s):  
Molecular Dynamics ◽  
Conformational Changes ◽  
Molecular Dynamics Method ◽  
Enhanced Sampling ◽  
Dynamics Method
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