Transferability of Quantum Topological Atoms in Terms of Electrostatic Interaction Energy

2006 ◽  
Vol 110 (50) ◽  
pp. 13578-13583 ◽  
Author(s):  
Michel Rafat ◽  
Majeed Shaik ◽  
Paul L. A. Popelier
Keyword(s):  
Interaction Energy ◽  
Electrostatic Interaction ◽  
Topological Atoms

Molecular tapes in the structure of isoguaninium chloride

2017 ◽  
Vol 74 (1) ◽  
pp. 108-112 ◽  
Author(s):  
Urszula Anna Budniak ◽  
Paulina Maria Dominiak
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Charge Density ◽  
Interaction Energy ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Structure

Isoguanine, an analogue of guanine, is of intrinsic interest as a noncanonical nucleobase. The crystal structure of isoguaninium chloride (systematic name: 6-amino-2-oxo-1H,7H-purin-3-ium chloride), C5H6N5O+·Cl−, has been determined by single-crystal X-ray diffraction. Structure analysis was supported by electrostatic interaction energy (E es) calculations based on charge density reconstructed with the UBDB databank. In the structure, two kinds of molecular tapes are observed, one parallel to (010) and the other parallel to (50\overline{4}). The tapes are formed by dimers of isoguaninium cations interacting with chloride anions. E es analysis indicates that cations in one kind of tape are oriented so as to minimize repulsive electrostatic interactions.

Fast analytical evaluation of intermolecular electrostatic interaction energies using the pseudoatom representation of the electron density. III. Application to crystal structures via the Ewald and direct summation methods

2020 ◽  
Vol 76 (6) ◽  
pp. 630-651
Author(s):  
Daniel Nguyen ◽  
Piero Macchi ◽  
Anatoliy Volkov
Keyword(s):  
Interaction Energy ◽  
Crystal Structures ◽  
Electron Density ◽  
Small Molecule ◽  
Electrostatic Interaction ◽  
Multipole Moment ◽  
Interaction Energies ◽  
Acta Cryst ◽  
Löwdin Α Function ◽  
Direct Summation

The previously reported exact potential and multipole moment (EP/MM) method for fast and accurate evaluation of the intermolecular electrostatic interaction energies using the pseudoatom representation of the electron density [Volkov, Koritsanszky & Coppens (2004). Chem. Phys. Lett. 391, 170–175; Nguyen, Kisiel & Volkov (2018). Acta Cryst. A74, 524–536; Nguyen & Volkov (2019). Acta Cryst. A75, 448–464] is extended to the calculation of electrostatic interaction energies in molecular crystals using two newly developed implementations: (i) the Ewald summation (ES), which includes interactions up to the hexadecapolar level and the EP correction to account for short-range electron-density penetration effects, and (ii) the enhanced EP/MM-based direct summation (DS), which at sufficiently large intermolecular separations replaces the atomic multipole moment approximation to the electrostatic energy with that based on the molecular multipole moments. As in the previous study [Nguyen, Kisiel & Volkov (2018). Acta Cryst. A74, 524–536], the EP electron repulsion integral is evaluated analytically using the Löwdin α-function approach. The resulting techniques, incorporated in the XDPROP module of the software package XD2016, have been tested on several small-molecule crystal systems (benzene, L-dopa, paracetamol, amino acids etc.) and the crystal structure of a 181-atom decapeptide molecule (Z = 4) using electron densities constructed via the University at Buffalo Aspherical Pseudoatom Databank [Volkov, Li, Koritsanszky & Coppens (2004). J. Phys. Chem. A, 108, 4283–4300]. Using a 2015 2.8 GHz Intel Xeon E3-1505M v5 computer processor, a 64-bit implementation of the Löwdin α-function and one of the higher optimization levels in the GNU Fortran compiler, the ES method evaluates the electrostatic interaction energy with a numerical precision of at least 10−5 kJ mol−1 in under 6 s for any of the tested small-molecule crystal structures, and in 48.5 s for the decapeptide structure. The DS approach is competitive in terms of precision and speed with the ES technique only for crystal structures of small molecules that do not carry a large molecular dipole moment. The electron-density penetration effects, correctly accounted for by the two described methods, contribute 28–64% to the total electrostatic interaction energy in the examined systems, and thus cannot be neglected.

scholarly journals New Ligands and New Insights for Vitamin D Receptor from Charge Density

2014 ◽  
Vol 70 (a1) ◽  
pp. C966-C966
Author(s):  
Maura Malińska ◽  
Andrzej Kutner ◽  
Krzysztof Woźniak
Keyword(s):  
Vitamin D ◽  
Hydrogen Bonds ◽  
Charge Density ◽  
Interaction Energy ◽  
Vitamin D Receptor ◽  
Electrostatic Interaction ◽  
Interaction Energies ◽  
Average Strength ◽  
Vitamin D Analogs ◽  
Wide Range

Vitamin D protective effects result from its role as a nuclear transcription factor that regulates cell growth, differentiation, and a wide range of cellular mechanisms crucial to the development and progression of cancer.[1] Many academic investigators and pharmaceutical companies try to develop calcitriol analogs that exhibit equal or even increased anti-proliferative activity while exhibiting a reduced tendency to cause hypercalcemia. Analysis of 24 Vitamin D analogs bearing similar molecular structures with a complex of a Vitamin D Receptor (VDR) enabled the design of new agonists (TB1, TB2, TB3 and TB4). Undertaken approach was to minimize the electrostatic interaction energies available after the reconstruction of charge density with the aid of the pseudoatom databank (UBDB[2]). Comprehensive studies revealed 29 residues crucial for agonist binding. Trp286, which is specific to VDR among the representatives of the Nuclear Receptor Family, plays the crucial role of positioning the ligand forming dispersive interactions, mostly C-H...π, with an average strength of -4 kcal mol-1. The ligand binding pocket is primarily composed of hydrophobic residues, however there are 6 hydrogen bonds characteristic for all the ligands. They electrostatic interaction energies strongly contribute to the total interaction energy, with an average strength of -8, -19, -11 and -12 kcal mol-1 for hydrogen bonds to Ser237, Arg274, Ser278 and Tyr143. The aliphatic chain of the Vitamin D analogs adopt an extended conformation and the 25-hydroxyl group is hydrogen bonded to His305 and His397 with electrostatic interaction energies of -13 and -11 kcal mol-1. The geometries of complexes of the proposed ligand with VDR were obtained by the docking procedure implemented in Autodock4.3[3]. New agonsits form all mentioned before interactions with VDR. The final results of electrostatic interaction energy for TB1 and TB2 are -153 and -120 kcal mol-1, and this results are the smallest among all studied Vitamin D analogs.

scholarly journals Combining Molecular Dynamic Information and an Aspherical-Atom Data Bank in the Evaluation of the Electrostatic Interaction Energy in Multimeric Protein-Ligand Complex: A Case Study for HIV-1 Protease

2021 ◽  
Author(s):  
Prashant Kumar ◽  
Paulina Dominiak
Keyword(s):  
Interaction Energy ◽  
Molecular Dynamic ◽  
Binding Affinity ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
Data Bank ◽  
Scoring Functions ◽  
Protein Ligand Interactions ◽  
Ligand Interactions ◽  
Hiv 1

<div> <div> <div> <p>Computational analysis of protein-ligand interactions is of crucial importance for drug discovery. Assessment of ligand binding energy allows us to have a glimpse on the potential of a small organic molecule to be a ligand to the binding site of a protein target. Available scoring functions such as in docking programs, we could say that they all rely on equations that sum each type of protein-ligand interactions to model the binding affinity. Most of the scoring functions consider electrostatic interactions involving the protein and the ligand. Electrostatic interactions contribute one of the most important part of total interaction energies between macromolecules, unlike dispersion forces they are highly directional and therefore dominate the nature of molecular packing in crystals and in biological complexes and contribute significantly to differences in inhibition strength among related enzyme inhibitors. In this paper, complexes of HIV-1 protease with inhibitor molecules (JE-2147 and Darunavir) have been analysed using charge densities from a transferable aspherical-atom data bank. Moreover, we analyse the electrostatic interaction energy for an ensemble of structures using molecular dynamic simulation to highlight the main features related to the importance of this interaction for binding affinity. </p> </div> </div> </div>

scholarly journals Combining Molecular Dynamic Information and an Aspherical-Atom Data Bank in the Evaluation of the Electrostatic Interaction Energy in Multimeric Protein-Ligand Complex: A Case Study for HIV-1 Protease

2021 ◽  
Author(s):  
Prashant Kumar ◽  
Paulina Dominiak
Keyword(s):  
Interaction Energy ◽  
Molecular Dynamic ◽  
Binding Affinity ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
Data Bank ◽  
Scoring Functions ◽  
Protein Ligand Interactions ◽  
Ligand Interactions ◽  
Hiv 1

<div> <div> <div> <p>Computational analysis of protein-ligand interactions is of crucial importance for drug discovery. Assessment of ligand binding energy allows us to have a glimpse on the potential of a small organic molecule to be a ligand to the binding site of a protein target. Available scoring functions such as in docking programs, we could say that they all rely on equations that sum each type of protein-ligand interactions to model the binding affinity. Most of the scoring functions consider electrostatic interactions involving the protein and the ligand. Electrostatic interactions contribute one of the most important part of total interaction energies between macromolecules, unlike dispersion forces they are highly directional and therefore dominate the nature of molecular packing in crystals and in biological complexes and contribute significantly to differences in inhibition strength among related enzyme inhibitors. In this paper, complexes of HIV-1 protease with inhibitor molecules (JE-2147 and Darunavir) have been analysed using charge densities from a transferable aspherical-atom data bank. Moreover, we analyse the electrostatic interaction energy for an ensemble of structures using molecular dynamic simulation to highlight the main features related to the importance of this interaction for binding affinity. </p> </div> </div> </div>

scholarly journals A rush to explore protein–ligand electrostatic interaction energy with Charger

2021 ◽  
Vol 77 (10) ◽  
pp. 1292-1304 ◽  
Author(s):  
Vedran Vuković ◽  
Theo Leduc ◽  
Zoe Jelić-Matošević ◽  
Claude Didierjean ◽  
Frédérique Favier ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Interaction Energy ◽  
Electrostatic Interaction ◽  
Glutathione Transferase ◽  
Multipole Moment ◽  
Point Of View ◽  
Electrostatic Energy ◽  
Electron Densities ◽  
Acta Cryst ◽  
Ligand Interaction

The mutual penetration of electron densities between two interacting molecules complicates the computation of an accurate electrostatic interaction energy based on a pseudo-atom representation of electron densities. The numerical exact potential and multipole moment (nEP/MM) method is time-consuming since it performs a 3D integration to obtain the electrostatic energy at short interaction distances. Nguyen et al. [(2018), Acta Cryst. A74, 524–536] recently reported a fully analytical computation of the electrostatic interaction energy (aEP/MM). This method performs much faster than nEP/MM (up to two orders of magnitude) and remains highly accurate. A new program library, Charger, contains an implementation of the aEP/MM method. Charger has been incorporated into the MoProViewer software. Benchmark tests on a series of small molecules containing only C, H, N and O atoms show the efficiency of Charger in terms of execution time and accuracy. Charger is also powerful in a study of electrostatic symbiosis between a protein and a ligand. It determines reliable protein–ligand interaction energies even when both contain S atoms. It easily estimates the individual contribution of every residue to the total protein–ligand electrostatic binding energy. Glutathione transferase (GST) in complex with a benzophenone ligand was studied due to the availability of both structural and thermodynamic data. The resulting analysis highlights not only the residues that stabilize the ligand but also those that hinder ligand binding from an electrostatic point of view. This offers new perspectives in the search for mutations to improve the interaction between the two partners. A proposed mutation would improve ligand binding to GST by removing an electrostatic obstacle, rather than by the traditional increase in the number of favourable contacts.

Ein statistisches Modell der Ladungsverteilung in quellungsfähigen glimmerartigen Schichtsilicaten mit beidellitischer Ladungsverteilung / A Statistical Model of the Charge Distribution in Beidellitic and Swelling Mica-Type Layer Silicates

1974 ◽  
Vol 29 (1-2) ◽  
pp. 44-48 ◽  
Author(s):  
Günter Schön ◽  
Armin Weiss
Keyword(s):  
Statistical Model ◽  
Interaction Energy ◽  
Charge Distribution ◽  
Electrostatic Interaction ◽  
Exchangeable Cations ◽  
Water Molecules ◽  
Layer Silicates ◽  
Type Layer

The charge distribution in mica-type layer silicates, which are capable of intercrystalline swelling, is discussed on the basis of a statistical model. The model explains the distribution of exchangeable cations and water molecules onto the geometrically identical lattice sites and simplifies the calculation of the electrostatic interaction energy between adjacent layers.

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