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 ◽  
...  

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.

2015 ◽  
Vol 61 (6) ◽  
pp. 712-716 ◽  
Author(s):  
I.V. Oferkin ◽  
A.V. Sulimov ◽  
E.V. Katkova ◽  
D.K. Kutov ◽  
F.V. Grigoriev ◽  
...  

The accuracy ofthe protein-ligand binding energy calculations andligand positioning isstrongly influenced by the choice of the docking target function. This work demonstrates the evaluation of the five different target functions used in docking: functions based on MMFF94 force field and functions based on PM7 quantum-chemical method accounting orwithout accounting the implicit solvent model (PCM, COSMO or SGB). For these purposes the ligand positions corresponding to the minima of the target function and the experimentally known ligand positions in the protein active site (crystal ligand positions) were compared. Each function was examined on the same test-set of 16 protein-ligand complexes. The new parallelized docking program FLM based on Monte Carlo search algorithm was developed to perform the comprehensive low-energy minima search and to calculate the protein-ligand binding energy. This study demonstrates that the docking target function based on the MMFF94 force field can be used to detect the crystal or near crystal positions of the ligand by the finding the low-energy local minima spectrum of the target function. The importance of solvent accounting in the docking process for the accurate ligand positioning is also shown. The accuracy of the ligand positioning as well as the correlation between the calculated and experimentally determined protein-ligand binding energies are improved when the MMFF94 force field is substituted by the new PM7 method with implicit solvent accounting.


2016 ◽  
Vol 9 (2) ◽  
pp. 89-94 ◽  
Author(s):  
Martin Michalík ◽  
Vladimír Lukeš

AbstractThe validation of octanol-water partition coefficients (logP) quantum chemical calculations is presented for 27 alkane alcohols. The chemical accuracy of predicted logPvalues was estimated for six DFT functionals (B3LYP, PBE0, M06-2X, ωB97X-D, B97-D3, M11) and three implicit solvent models. Triple-zeta basis set 6-311++G(d,p) was employed. The best linear correlation with the experimental logPvalues was achieved for the B3LYP and B97-D3 functionals combined with the SMD model. On the other hand, no linearity was found when IEF-PCM or C-PCM implicit models were employed.


2014 ◽  
Vol 5 ◽  
pp. 668-676 ◽  
Author(s):  
Wolfgang B Schneider ◽  
Alexander A Auer

In order to simulate electrochemical reactions in the framework of quantum chemical methods, density functional theory, methods can be devised that explicitly include the electrochemical potential. In this work we discuss a Grand Canonical approach in the framework of density functional theory in which fractional numbers of electrons are used to represent an open system in contact with an electrode at a given electrochemical potential. The computational shortcomings and the additional effort in such calculations are discussed. An ansatz for a SCF procedure is presented, which can be applied routinely and only marginally increases the computational effort of standard constant electron number approaches. In combination with the common implicit solvent models this scheme can become a powerful tool, especially for the investigation of omnipresent non-faradaic effects in electrochemistry.


2020 ◽  
Author(s):  
Rae Corrigan ◽  
Guowei Qi ◽  
Andrew Thiel ◽  
Jack Lynn ◽  
Brandon Walker ◽  
...  

Computational protein design, ab initio protein/RNA folding, and protein-ligand screening can be too computationally demanding for explicit treatment of solvent. For these applications, implicit solvent offers a compelling alternative, which we describe here for the polarizable atomic multipole AMOEBA force field based on three treatments of continuum electrostatics: numerical solutions to the Poisson-Boltzmann equation (PBE), the domain-decomposition Conductor-like Screening Model (ddCOSMO) approximation to the PBE, and the analytic generalized Kirkwood (GK) approximation. The continuum electrostatic models are combined with a nonpolar estimator based on novel cavitation and dispersion terms. Electrostatic model parameters are numerically optimized using a least squares style target function based on a library of 103 small molecule solvation free energy differences. Mean signed errors for the APBS, ddCOSMO, and GK models are 0.05, 0.00, and 0.00 kcal/mol, respectively, while the mean unsigned errors are 0.70, 0.63, and 0.51 kcal/mol, respectively. Validation of the electrostatic response of the resulting implicit solvents, which are available in the Tinker (or Tinker-HP), OpenMM, and Force Field X software packages, is based on comparisons to explicit solvent simulations for a series of proteins and nucleic acids. Overall, the emergence of performative implicit solvent models for polarizable force fields will open the door to their use for folding and design applications.<br>


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