Solvent models for protein-ligand binding: Comparison of implicit solvent poisson and surface generalized born models with explicit solvent simulations

2001 ◽  
Vol 22 (6) ◽  
pp. 591-607 ◽  
Author(s):  
Linda Yu Zhang ◽  
Emilio Gallicchio ◽  
Richard A. Friesner ◽  
Ronald M. Levy
Keyword(s):  
Ligand Binding ◽  
Implicit Solvent ◽  
Generalized Born ◽  
Solvent Models ◽  
Explicit Solvent

scholarly journals The Role of Displacing Confined Solvent in the Conformational Equilibrium of β-Cyclodextrin

2019 ◽  
Author(s):  
Peng He ◽  
Sheila Sarkar ◽  
Emilio Gallicchio ◽  
Tom Kurtzman ◽  
Lauren Wickstrom
Keyword(s):  
Conformational Equilibrium ◽  
Implicit Solvent ◽  
Theory Analysis ◽  
State Behavior ◽  
Generalized Born ◽  
Solvent Models ◽  
Explicit Solvent ◽  
Dynamics Simulations ◽  
Opening And Closing

<p>This study investigates the role of hydration and its relationship to the conformational equilibrium of the host molecule β-cyclodextrin. Molecular dynamics simulations indicate that the unbound β-cyclodextrin exhibits two state behavior in explicit solvent due to the opening and closing of its cavity. In implicit solvent, these transitions are not observed and there is one dominant conformation of β-cyclodextrin with an open cavity. Based on these observations, we investigate the hypothesis that the expulsion of thermodynamically unfavorable water molecules into the bulk plays an important role in controlling the accessibility of the closed macrostate at room temperature. We compare the results of the molecular mechanics analytical generalized Born plus non-polar solvation approach to those obtained through Grid Inhomogeneous Solvation Theory analysis with explicit solvation to elucidate the thermodynamic forces at play. The calculations help to illustrate the deficiencies of continuum solvent models and demonstrate the key role of the thermodynamics of enclosed hydration in driving the conformational equilibrium of molecules in solution. </p>

scholarly journals The Role of Displacing Confined Solvent in the Conformational Equilibrium of β-Cyclodextrin

2019 ◽  
Author(s):  
Peng He ◽  
Sheila Sarkar ◽  
Emilio Gallicchio ◽  
Tom Kurtzman ◽  
Lauren Wickstrom
Keyword(s):  
Conformational Equilibrium ◽  
Implicit Solvent ◽  
Theory Analysis ◽  
State Behavior ◽  
Generalized Born ◽  
Solvent Models ◽  
Explicit Solvent ◽  
Dynamics Simulations ◽  
Opening And Closing

<p>This study investigates the role of hydration and its relationship to the conformational equilibrium of the host molecule β-cyclodextrin. Molecular dynamics simulations indicate that the unbound β-cyclodextrin exhibits two state behavior in explicit solvent due to the opening and closing of its cavity. In implicit solvent, these transitions are not observed and there is one dominant conformation of β-cyclodextrin with an open cavity. Based on these observations, we investigate the hypothesis that the expulsion of thermodynamically unfavorable water molecules into the bulk plays an important role in controlling the accessibility of the closed macrostate at room temperature. We compare the results of the molecular mechanics analytical generalized Born plus non-polar solvation approach to those obtained through Grid Inhomogeneous Solvation Theory analysis with explicit solvation to elucidate the thermodynamic forces at play. The calculations help to illustrate the deficiencies of continuum solvent models and demonstrate the key role of the thermodynamics of enclosed hydration in driving the conformational equilibrium of molecules in solution. </p>

VERIFICATION OF THE GENERALIZED BORN MODEL AT SHORT DISTANCES

2013 ◽  
Vol 13 (06) ◽  
pp. 1340020
Author(s):  
XIAOCHUAN TANG ◽  
YONG DUAN
Keyword(s):  
Analytical Solutions ◽  
Md Simulations ◽  
Solvation Energy ◽  
Implicit Solvent ◽  
Generalized Born ◽  
Simple Description ◽  
Born Model ◽  
Solvent Models ◽  
Potential Methods ◽  
Gb Model

The generalized Born (GB) model, one of the implicit solvent models, is widely applied in molecular dynamics (MD) simulations as a simple description of the solvation effect. In the GB model, an empirical function called the Still's formula, with the algorithmic simplicity, is utilized to calculate the solvation energy due to the polarization, termed as ΔG pol . Applications of the GB model have exhibited reasonable accuracy and high computational efficiency. However, there is still room for improvements. Most of the attempts to improve the GB model focus on optimizing effective Born radii. Contrarily, limited researches have been performed to improve the feasibility of the Still's formula. In this paper, analytical methods was applied to investigate the validity of the Still's formula at short distance. Taking advantage of the toroidal coordinates and Mehler–Fock transform, the analytical solutions of the GB model at short distances was derived explicitly for the first time. Additionally, the solvation energy was numerically computed using proper algorithms based on the analytical solutions and compared with ΔG pol calculated in the GB model. With the analysis on the deficiencies of the Still's formula at short distances, potential methods to improve the validity of the GB model were discussed.

Generalized Born implicit solvent models for small molecule hydration free energies

2017 ◽  
Vol 19 (2) ◽  
pp. 1677-1685 ◽  
Author(s):  
Martin Brieg ◽  
Julia Setzler ◽  
Steffen Albert ◽  
Wolfgang Wenzel
Keyword(s):  
Free Energy ◽  
Small Molecules ◽  
Implicit Solvent ◽  
Free Energies ◽  
Hydration Free Energy ◽  
Energy Estimation ◽  
Generalized Born ◽  
Solvent Models ◽  
Molecular Force ◽  
Implicit Solvent Models

Hydration free energy estimation of small molecules from all-atom simulations was widely investigated in recent years, as it provides an essential test of molecular force fields and our understanding of solvation effects.

Thermodynamics of Helix formation in small peptides of varying lengthin vacuo, implicit solvent and explicit solvent: Comparison between AMBER force fields

2019 ◽  
Vol 18 (03) ◽  
pp. 1950015
Author(s):  
Zhaoxi Sun ◽  
Xiaohui Wang
Keyword(s):  
Amino Acids ◽  
Free Energy ◽  
Hydrogen Bonds ◽  
Force Fields ◽  
Implicit Solvent ◽  
Conformational Ensemble ◽  
Helix Formation ◽  
Solvent Models ◽  
Explicit Solvent ◽  
Amber Force Fields

Helix formation is of great significance in protein folding. The helix-forming tendencies of amino acids are accumulated along the sequence to determine the helix-forming tendency of peptides. Computer simulation can be used to model this process in atomic details and give structural insights. In the current work, we employ equilibrate-state free energy simulation to systematically study the folding/unfolding thermodynamics of a series of mutated peptides. Two AMBER force fields including AMBER99SB and AMBER14SB are compared. The new 14SB force field uses refitted torsion parameters compared with 99SB and they share the same atomic charge scheme. We find that in vacuo the helix formation is mutation dependent, which reflects the different helix propensities of different amino acids. In general, there are helix formers, helix indifferent groups and helix breakers. The helical structure becomes more favored when the length of the sequence becomes longer, which arises from the formation of additional backbone hydrogen bonds in the lengthened sequence. Therefore, the helix indifferent groups and helix breakers will become helix formers in long sequences. Also, protonation-dependent helix formation is observed for ionizable groups. In 14SB, the helical structures are more stable than in 99SB and differences can be observed in their grouping schemes, especially in the helix indifferent group. In solvents, all mutations are helix indifferent due to protein–solvent interactions. The decrease in the number of backbone hydrogen bonds is the same with the increase in the number of protein–water hydrogen bonds. The 14SB in explicit solvent is able to capture the free energy minima in the helical state while 14SB in implicit solvent, 99SB in explicit solvent and 99SB in implicit solvent cannot. The helix propensities calculated under 14SB agree with the corresponding experimental values, while the 99SB results obviously deviate from the references. Hence, implicit solvent models are unable to correctly describe the thermodynamics even for the simple helix formation in isolated peptides. Well-developed force fields and explicit solvents are needed to correctly describe the protein dynamics. Aside from the free energy, differences in conformational ensemble under different force fields in different solvent models are observed. The numbers of hydrogen bonds formed under different force fields agree and they are mostly determined by the solvent model.

scholarly journals Evaluation of Docking Target Functions by the Comprehensive Investigation of Protein-Ligand Energy Minima

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Igor V. Oferkin ◽  
Ekaterina V. Katkova ◽  
Alexey V. Sulimov ◽  
Danil C. Kutov ◽  
Sergey I. Sobolev ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Force Field ◽  
Quantum Chemical ◽  
Target Function ◽  
Binding Energies ◽  
Low Energy ◽  
Implicit Solvent ◽  
Energy Calculation ◽  
Solvent Models ◽  
Docking Program

The adequate choice of the docking target function impacts the accuracy of the ligand positioning as well as the accuracy of the protein-ligand binding energy calculation. To evaluate a docking target function we compared positions of its minima with the experimentally known pose of the ligand in the protein active site. We evaluated five docking target functions based on either the MMFF94 force field or the PM7 quantum-chemical method with or without implicit solvent models: PCM, COSMO, and SGB. Each function was tested on the same set of 16 protein-ligand complexes. For exhaustive low-energy minima search the novel MPI parallelized docking program FLM and large supercomputer resources were used. Protein-ligand binding energies calculated using low-energy minima were compared with experimental values. It was demonstrated that the docking target function on the base of the MMFF94 force field in vacuo can be used for discovery of native or near native ligand positions by finding the low-energy local minima spectrum of the target function. The importance of solute-solvent interaction for the correct ligand positioning is demonstrated. It is shown that docking accuracy can be improved by replacement of the MMFF94 force field by the new semiempirical quantum-chemical PM7 method.

scholarly journals Bridging the experiment-calculation divide: machine learning corrections to redox potential calculations in implicit and explicit solvent models

2021 ◽  
Author(s):  
Eugen Hruska ◽  
Ariel Gale ◽  
Fang Liu
Keyword(s):  
Machine Learning ◽  
Redox Potential ◽  
Density Functional ◽  
Implicit Solvent ◽  
Systematic Bias ◽  
Redox Potentials ◽  
Solvent Models ◽  
Explicit Solvent ◽  
Solvent Model ◽  
Implicit And Explicit

Prediction of redox potentials is essential for catalysis and energy storage. Although density functional theory (DFT) calculations have enabled rapid redox potential predictions for numerous compounds, prominent errors persist compared to experimental measurements. In this work, we develop machine learning (ML) models to reduce the errors of redox potential calculations in both implicit and explicit solvent models. Training and testing of the ML correction models are based on the diverse ROP313 dataset with experimental redox potentials measured for organic and organometallic compounds in a variety of solvents. For the implicit solvent approach, our ML models can reduce both the systematic bias and the number of outliers. ML corrected redox potentials also demonstrate less sensitivity to DFT functional choice. For the explicit solvent approach, we significantly reduce the computational costs by embedding the microsolvated cluster in implicit bulk solvent, obtaining converged redox potential results with a smaller solvation shell. This combined implicit-explicit solvent model, together with GPU-accelerated quantum chemistry methods, enabled rapid generation of a large dataset of explicit-solvent-calculated redox potentials for 165 organic compounds, allowing detailed investigation of the error sources in explicit solvent redox potential calculations.

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