Spherical tensor approach to multipole expansions. I. Electrostatic interactions

1976 ◽  
Vol 54 (5) ◽  
pp. 505-512 ◽  
Author(s):  
C. G. Gray
Keyword(s):  
External Field ◽  
Interaction Energy ◽  
Charge Distribution ◽  
Electrostatic Interaction ◽  
Electrostatic Field ◽  
Spherical Harmonic ◽  
Electrostatic Interactions ◽  
Tensor Method ◽  
Multipole Expansions ◽  
A Charge

Using spherical harmonic expansions, the electrostatic field due to a given charge distribution, the interaction energy of a charge distribution with a given external field, and the electrostatic interaction energy of two charge distributions are decomposed into multipolar components. Extensive use is made of symmetry arguments. Comparisons with the Cartesian tensor method are also given.

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.

Spherical tensor approach to multipole expansions. II. Magnetostatic interactions

1976 ◽  
Vol 54 (5) ◽  
pp. 513-518 ◽  
Author(s):  
C. G. Gray ◽  
P. J. Stiles
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Interaction Energy ◽  
Current Distribution ◽  
Spherical Harmonic ◽  
Magnetostatic Interaction ◽  
Multipole Expansions ◽  
The Magnetic Field ◽  
A Current ◽  
Magnetostatic Interactions

The magnetic field due to a given current distribution, the interaction energy of a current distribution with an arbitrary external magnetic field, and the magnetostatic interaction energy between two current distributions are decomposed into multipolar components using spherical harmonic expansions. Diamagnetic interactions and the spin contributions to the multipole expansions are also discussed.

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>

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.

scholarly journals Charge density studies of interactions in macromolecules – the case of sunitinib

2014 ◽  
Vol 70 (a1) ◽  
pp. C970-C970
Author(s):  
Maura Malińska ◽  
Katarzyna Jarzembska ◽  
Anna Goral ◽  
Andrzej Kutner ◽  
Krzysztof Woźniak ◽  
...  
Keyword(s):  
Charge Density ◽  
Interaction Energy ◽  
Electron Density ◽  
Electrostatic Interaction ◽  
Tyrosine Kinases ◽  
Electrostatic Interactions ◽  
Kinase Inhibitor ◽  
Topological Analysis ◽  
3D Structure ◽  
X Ray

Electron density is a key factor in determining properties of molecules. Knowledge of the electron density distribution allows to determine not only the 3D structure of molecules, but also various one-electron properties (electric moments, electrostatic potential, electrostatic interaction energy, etc.). X-ray diffraction is a great tool for obtaining this kind of information. For macromolecules, however, quantitative determination of charge density from experiment is possible on rare occasions only. We will present that with the University at Buffalo pseudoatom database (UBDB) approach [1,2] it is now possible to reconstruct electron density of any macromolecular system for which atomic coordinates are available. The approach is fast and opens an excellent opportunity to investigate macromolecular complexes by means of topological analysis of electron density (and derivatives thereof), electrostatic interaction energy analysis, and many others. The results of our studies on sunitinib (SU) will illustrate the possibilities of the approach. SU is an inhibitor of tyrosine kinases and was approved as a drug in 2006. Comprehensive analysis of the SU malate crystal and SU complexes with a series of protein kinases was carried out. The high resolution single crystal X-ray measurement and UBDB approach served as the basis for the reconstruction of the charge density of SU and the protein complexes. Hirshfeld surface and topological analyses revealed a similar interaction pattern in the SU malate crystal to that in the protein binding pockets. SU forms nine preserved bond paths corresponding to hydrogen bonds and also to the C-H...O and C-H...π contacts common for all analyzed kinases. It interacts typically with similar electrostatic interaction energy with the studied proteins and can adjust its conformation to fit the binding pocket in a way to enhance the electrostatic interactions. Such behavior can be responsible for a broad spectrum of action of SU as kinase inhibitor.

Berechnung der elektrostatischen Wechselwirkungsenergie für ein Kristallgitter zylindersymmetrischer Teilchen

1971 ◽  
Vol 26 (3) ◽  
pp. 561-568
Author(s):  
A. Neckel ◽  
P. Kuzmany ◽  
G. Vinek
Keyword(s):  
Crystal Lattice ◽  
Interaction Energy ◽  
Charge Distribution ◽  
Electrostatic Interaction ◽  
Cylindrical Symmetry ◽  
Multipole Moments ◽  
The Real ◽  
Crystal Potential ◽  
Lattice Sums

Abstract A method is presented for the calculation of the electrostatic interaction energy in a crystal lattice taking into account the real charge distribution of the particles. For this purpose the charge distribution of a particle is represented by a superposition of multipole moments. The crystal potential is expanded into amultipole expansion, the resulting lattice sums being evaluated according to Ewald's method. The present paper is restricted to the treatment of molecules or molecule-ions of cylindrical symmetry.

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

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3872
Author(s):  
Prashant Kumar ◽  
Paulina Maria Dominiak
Keyword(s):  
Interaction Energy ◽  
Molecular Dynamic ◽  
Binding Affinity ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
Scoring Functions ◽  
Ligand Complex ◽  
Protein Ligand Interactions ◽  
Ligand Interactions ◽  
Hiv 1

Computational analysis of protein–ligand interactions is of crucial importance for drug discovery. Assessment of ligand binding energy allows us to have a glimpse of 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, all rely on equations that sum each type of protein–ligand interactions in order to predict the binding affinity. Most of the scoring functions consider electrostatic interactions involving the protein and the ligand. Electrostatic interactions constitute one of the most important part of total interactions 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 study, complexes of HIV-1 protease with inhibitor molecules (JE-2147 and darunavir) were analyzed by using charge densities from the transferable aspherical-atom University at Buffalo Databank (UBDB). Moreover, we analyzed the electrostatic interaction energy for an ensemble of structures, using molecular dynamic simulations to highlight the main features of electrostatic interactions important for binding affinity.

scholarly journals Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

2011 ◽  
Vol 2 ◽  
pp. 552-560 ◽  
Author(s):  
Miriam Jaafar ◽  
Oscar Iglesias-Freire ◽  
Luis Serrano-Ramón ◽  
Manuel Ricardo Ibarra ◽  
Jose Maria de Teresa ◽  
...  
Keyword(s):  
Long Range ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Superparamagnetic Nanoparticles ◽  
Kelvin Probe Force Microscopy ◽  
Magnetic Interactions ◽  
Kelvin Probe ◽  
Force Microscopy

The most outstanding feature of scanning force microscopy (SFM) is its capability to detect various different short and long range interactions. In particular, magnetic force microscopy (MFM) is used to characterize the domain configuration in ferromagnetic materials such as thin films grown by physical techniques or ferromagnetic nanostructures. It is a usual procedure to separate the topography and the magnetic signal by scanning at a lift distance of 25–50 nm such that the long range tip–sample interactions dominate. Nowadays, MFM is becoming a valuable technique to detect weak magnetic fields arising from low dimensional complex systems such as organic nanomagnets, superparamagnetic nanoparticles, carbon-based materials, etc. In all these cases, the magnetic nanocomponents and the substrate supporting them present quite different electronic behavior, i.e., they exhibit large surface potential differences causing heterogeneous electrostatic interaction between the tip and the sample that could be interpreted as a magnetic interaction. To distinguish clearly the origin of the tip–sample forces we propose to use a combination of Kelvin probe force microscopy (KPFM) and MFM. The KPFM technique allows us to compensate in real time the electrostatic forces between the tip and the sample by minimizing the electrostatic contribution to the frequency shift signal. This is a great challenge in samples with low magnetic moment. In this work we studied an array of Co nanostructures that exhibit high electrostatic interaction with the MFM tip. Thanks to the use of the KPFM/MFM system we were able to separate the electric and magnetic interactions between the tip and the sample.

The Electrostatic Moments of a Charge Distribution

1997 ◽  
Author(s):  
Philip Coppens
Keyword(s):  
Dipole Moment ◽  
Charge Distribution ◽  
Dipole Moments ◽  
Practical Importance ◽  
Diffraction Method ◽  
Quadrupole Moments ◽  
Charge Densities ◽  
Moment Vector ◽  
Experimental Values ◽  
A Charge

The moments of a charge distribution provide a concise summary of the nature of that distribution. They are suitable for quantitative comparison of experimental charge densities with theoretical results. As many of the moments can be obtained by spectroscopic and dielectric methods, the comparison between techniques can serve as a calibration of experimental and theoretical charge densities. Conversely, since the full charge density is not accessible by the other experimental methods, the comparison provides an interpretation of the results of the complementary physical techniques. The electrostatic moments are of practical importance, as they occur in the expressions for intermolecular interactions and the lattice energies of crystals. The first electrostatic moment from X-rays was obtained by Stewart (1970), who calculated the dipole moment of uracil from the least-squares valence-shell populations of each of the constituent atoms of the molecule. Stewart’s value of 4.0 ± 1.3 D had a large experimental uncertainty, but is nevertheless close to the later result of 4.16 ± 0.4 D (Kulakowska et al. 1974), obtained from capacitance measurements of a solution in dioxane. The diffraction method has the advantage that it gives not only the magnitude but also the direction of the dipole moment. Gas-phase microwave measurements are also capable of providing all three components of the dipole moment, but only the magnitude is obtained from dielectric solution measurements. We will use an example as illustration. The dipole moment vector for formamide has been determined both by diffraction and microwave spectroscopy. As the diffraction experiment measures a continuous charge distribution, the moments derived are defined in terms of the method used for space partitioning, and are not necessarily equal. Nevertheless, the results from different techniques agree quite well. A comprehensive review on molecular electric moments from X-ray diffraction data has been published by Spackman (1992). Spackman points out that despite a large number of determinations of molecular dipole moments and a few determinations of molecular quadrupole moments, it is not yet widely accepted that diffraction methods lead to valid experimental values of the electrostatic moments.

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