On the Adsorption of Aspartate Derivatives to Calcite Surfaces in Aqueous Environment

2020 ◽  
Author(s):  
Robert Stepic ◽  
Lara Jurković ◽  
Ksenia Klementyeva ◽  
Marko Ukrainczyk ◽  
Matija Gredičak ◽  
...  
Keyword(s):  
Active Sites ◽  
Realistic Model ◽  
Binding Energies ◽  
Inhibition Mechanism ◽  
Aqueous Environment ◽  
Binding Modes ◽  
Carboxylate Groups ◽  
Dissolved Ions ◽  
Living Organisms ◽  
Dynamics Simulations

In many living organisms, biomolecules interact favorably with various surfaces of calcium carbonate. In this work, we have considered the interactions of aspartate (Asp) derivatives, as models of complex biomolecules, with calcite. Using kinetic growth experiments, we have investigated the inhibition of calcite growth by Asp, Asp2 and Asp3.This entailed the determination of a step-pinning growth regime as well as the evaluation of the adsorption constants and binding free energies for the three species to calcite crystals. These latter values are compared to free energy profiles obtained from fully atomistic molecular dynamics simulations. When using a flat (104) calcite surface in the models, the measured trend of binding energies is poorly reproduced. However, a more realistic model comprised of a surface with an island containing edges and corners, yields binding energies that compare very well with experiments. Surprisingly, we find that most binding modes involve the positively charged, ammonium group. Moreover, while attachment of the negatively charged carboxylate groups is also frequently observed, it is always balanced by the aqueous solvation of an equal or greater number of carboxylates. These effects are observed on all calcite features including edges and corners, the latter being associated with dominant affinities to Asp derivatives. As these features are also precisely the active sites for crystal growth, the experimental and theoretical results point strongly to a growth inhibition mechanism whereby these sites become blocked, preventing further attachment of dissolved ions and halting further growth.

On the Adsorption of Aspartate Derivatives to Calcite Surfaces in Aqueous Environment

2020 ◽  
Author(s):  
Robert Stepic ◽  
Lara Jurković ◽  
Ksenia Klementyeva ◽  
Marko Ukrainczyk ◽  
Matija Gredičak ◽  
...  
Keyword(s):  
Active Sites ◽  
Realistic Model ◽  
Binding Energies ◽  
Inhibition Mechanism ◽  
Aqueous Environment ◽  
Binding Modes ◽  
Carboxylate Groups ◽  
Dissolved Ions ◽  
Living Organisms ◽  
Dynamics Simulations

In many living organisms, biomolecules interact favorably with various surfaces of calcium carbonate. In this work, we have considered the interactions of aspartate (Asp) derivatives, as models of complex biomolecules, with calcite. Using kinetic growth experiments, we have investigated the inhibition of calcite growth by Asp, Asp2 and Asp3.This entailed the determination of a step-pinning growth regime as well as the evaluation of the adsorption constants and binding free energies for the three species to calcite crystals. These latter values are compared to free energy profiles obtained from fully atomistic molecular dynamics simulations. When using a flat (104) calcite surface in the models, the measured trend of binding energies is poorly reproduced. However, a more realistic model comprised of a surface with an island containing edges and corners, yields binding energies that compare very well with experiments. Surprisingly, we find that most binding modes involve the positively charged, ammonium group. Moreover, while attachment of the negatively charged carboxylate groups is also frequently observed, it is always balanced by the aqueous solvation of an equal or greater number of carboxylates. These effects are observed on all calcite features including edges and corners, the latter being associated with dominant affinities to Asp derivatives. As these features are also precisely the active sites for crystal growth, the experimental and theoretical results point strongly to a growth inhibition mechanism whereby these sites become blocked, preventing further attachment of dissolved ions and halting further growth.

scholarly journals A Novel Integrated Way for Deciphering the Glycan Code for the FimH Lectin

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2794 ◽  
Author(s):  
Tetiana Dumych ◽  
Clarisse Bridot ◽  
Sébastien Gouin ◽  
Marc Lensink ◽  
Solomiya Paryzhak ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Bacterial Adhesion ◽  
Binding Energies ◽  
Conformational Space ◽  
Binding Modes ◽  
E Coli ◽  
Binding Enthalpy ◽  
Dynamics Simulations ◽  
Adhesion And Invasion

The fimbrial lectin FimH from uro- and enteropathogenic Escherichia coli binds with nanomolar affinity to oligomannose glycans exposing Manα1,3Man dimannosides at their non-reducing end, but only with micromolar affinities to Manα1,2Man dimannosides. These two dimannoses play a significantly distinct role in infection by E. coli. Manα1,2Man has been described early on as shielding the (Manα1,3Man) glycan that is more relevant to strong bacterial adhesion and invasion. We quantified the binding of the two dimannoses (Manα1,2Man and Manα1,3Man to FimH using ELLSA and isothermal microcalorimetry and calculated probabilities of binding modes using molecular dynamics simulations. Our experimentally and computationally determined binding energies confirm a higher affinity of FimH towards the dimannose Manα1,3Man. Manα1,2Man displays a much lower binding enthalpy combined with a high entropic gain. Most remarkably, our molecular dynamics simulations indicate that Manα1,2Man cannot easily take its major conformer from water into the FimH binding site and that FimH is interacting with two very different conformers of Manα1,2Man that occupy 42% and 28% respectively of conformational space. The finding that Manα1,2Man binding to FimH is unstable agrees with the earlier suggestion that E. coli may use the Manα1,2Man epitope for transient tethering along cell surfaces in order to enhance dispersion of the infection.

scholarly journals Potential Inhibitors for Novel Coronavirus Protease Identified by Virtual Screening of 606 Million Compounds

2020 ◽  
Vol 21 (10) ◽  
pp. 3626 ◽  
Author(s):  
André Fischer ◽  
Manuel Sellner ◽  
Santhosh Neranjan ◽  
Martin Smieško ◽  
Markus A. Lill
Keyword(s):  
Viral Infections ◽  
Chemical Space ◽  
Drug Repurposing ◽  
Close Relation ◽  
Binding Energies ◽  
Proteolytic Processing ◽  
Binding Modes ◽  
Novel Coronavirus ◽  
Dynamics Simulations ◽  
Potential Inhibitors

The rapid outbreak of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China followed by its spread around the world poses a serious global concern for public health. To this date, no specific drugs or vaccines are available to treat SARS-CoV-2 despite its close relation to the SARS-CoV virus that caused a similar epidemic in 2003. Thus, there remains an urgent need for the identification and development of specific antiviral therapeutics against SARS-CoV-2. To conquer viral infections, the inhibition of proteases essential for proteolytic processing of viral polyproteins is a conventional therapeutic strategy. In order to find novel inhibitors, we computationally screened a compound library of over 606 million compounds for binding at the recently solved crystal structure of the main protease (Mpro) of SARS-CoV-2. A screening of such a vast chemical space for SARS-CoV-2 Mpro inhibitors has not been reported before. After shape screening, two docking protocols were applied followed by the determination of molecular descriptors relevant for pharmacokinetics to narrow down the number of initial hits. Next, molecular dynamics simulations were conducted to validate the stability of docked binding modes and comprehensively quantify ligand binding energies. After evaluation of potential off-target binding, we report a list of 12 purchasable compounds, with binding affinity to the target protease that is predicted to be more favorable than that of the cocrystallized peptidomimetic compound. In order to quickly advise ongoing therapeutic intervention for patients, we evaluated approved antiviral drugs and other protease inhibitors to provide a list of nine compounds for drug repurposing. Furthermore, we identified the natural compounds (−)-taxifolin and rhamnetin as potential inhibitors of Mpro. Rhamnetin is already commercially available in pharmacies.

scholarly journals Inhibitors for Novel Coronavirus Protease Identified by Virtual Screening of 687 Million Compounds

2020 ◽  
Author(s):  
André Fischer ◽  
Manuel Sellner ◽  
Santhosh Neranjan ◽  
Markus A. Lill ◽  
Martin Smieško
Keyword(s):  
Viral Infections ◽  
Chemical Space ◽  
Binding Free Energy ◽  
Close Relation ◽  
Binding Energies ◽  
Proteolytic Processing ◽  
Binding Modes ◽  
Compound Library ◽  
Novel Coronavirus ◽  
Dynamics Simulations

The rapid outbreak of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China followed by its spread around the world poses a serious global concern for public health with almost 90000 people infected and thousands of fatalities. To conquer viral infections, the inhibition of proteases essential for proteolytic processing of viral polyproteins is a conventional therapeutic strategy. To this date, no specific drugs or vaccines are available to treat SARS-CoV-2 despite its close relation to the SARS-CoV-1 virus that caused a similar epidemic in 2003. Thus, there remains an urgent need for the development of specific antiviral therapeutics to conquer SARS-CoV-2. In order to find novel inhibitors, we computationally screened a compound library of over 687 million compounds for binding at the recently solved crystal structure of the main protease of SARS-CoV-2. A screening of such a vast chemical space for SARS-CoV-2 protease inhibitors has not been reported before. After shape screening, two docking protocols were applied followed by the determination of pharmacokinetically relevant molecular descriptors to narrow down the initial hits. Next, molecular dynamics simulations were conducted to validate the stability of docked binding modes and comprehensively quantify ligand binding energies. After evaluation of off-target binding, we report a list of 11 drug-like compounds with improved binding free energy to the target protease in contrast to the cocrystallized peptidomimetic lead compound that suffers from poor pharmacokinetic properties. Furthermore, we identified one potent binder with comparable properties from the natural compound library.

scholarly journals Potential Inhibitors for Novel Coronavirus Protease Identified by Virtual Screening of 606 Million Compounds

2020 ◽  
Author(s):  
André Fischer ◽  
Manuel Sellner ◽  
Santhosh Neranjan ◽  
Markus A. Lill ◽  
Martin Smieško
Keyword(s):  
Viral Infections ◽  
Chemical Space ◽  
Binding Free Energy ◽  
Close Relation ◽  
Binding Energies ◽  
Proteolytic Processing ◽  
Binding Modes ◽  
Compound Library ◽  
Novel Coronavirus ◽  
Dynamics Simulations

The rapid outbreak of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China followed by its spread around the world poses a serious global concern for public health with almost 90000 people infected and thousands of fatalities. To conquer viral infections, the inhibition of proteases essential for proteolytic processing of viral polyproteins is a conventional therapeutic strategy. To this date, no specific drugs or vaccines are available to treat SARS-CoV-2 despite its close relation to the SARS-CoV-1 virus that caused a similar epidemic in 2003. Thus, there remains an urgent need for the development of specific antiviral therapeutics to conquer SARS-CoV-2. In order to find novel inhibitors, we computationally screened a compound library of over 687 million compounds for binding at the recently solved crystal structure of the main protease of SARS-CoV-2. A screening of such a vast chemical space for SARS-CoV-2 protease inhibitors has not been reported before. After shape screening, two docking protocols were applied followed by the determination of pharmacokinetically relevant molecular descriptors to narrow down the initial hits. Next, molecular dynamics simulations were conducted to validate the stability of docked binding modes and comprehensively quantify ligand binding energies. After evaluation of off-target binding, we report a list of 11 drug-like compounds with improved binding free energy to the target protease in contrast to the cocrystallized peptidomimetic lead compound that suffers from poor pharmacokinetic properties. Furthermore, we identified one potent binder with comparable properties from the natural compound library.

scholarly journals Potential Inhibitors for Novel Coronavirus Protease Identified by Virtual Screening of 606 Million Compounds

2020 ◽  
Author(s):  
André Fischer ◽  
Manuel Sellner ◽  
Santhosh Neranjan ◽  
Markus A. Lill ◽  
Martin Smieško
Keyword(s):  
Viral Infections ◽  
Chemical Space ◽  
Binding Free Energy ◽  
Close Relation ◽  
Binding Energies ◽  
Proteolytic Processing ◽  
Binding Modes ◽  
Compound Library ◽  
Novel Coronavirus ◽  
Dynamics Simulations

The rapid outbreak of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China followed by its spread around the world poses a serious global concern for public health with almost 90000 people infected and thousands of fatalities. To conquer viral infections, the inhibition of proteases essential for proteolytic processing of viral polyproteins is a conventional therapeutic strategy. To this date, no specific drugs or vaccines are available to treat SARS-CoV-2 despite its close relation to the SARS-CoV-1 virus that caused a similar epidemic in 2003. Thus, there remains an urgent need for the development of specific antiviral therapeutics to conquer SARS-CoV-2. In order to find novel inhibitors, we computationally screened a compound library of over 687 million compounds for binding at the recently solved crystal structure of the main protease of SARS-CoV-2. A screening of such a vast chemical space for SARS-CoV-2 protease inhibitors has not been reported before. After shape screening, two docking protocols were applied followed by the determination of pharmacokinetically relevant molecular descriptors to narrow down the initial hits. Next, molecular dynamics simulations were conducted to validate the stability of docked binding modes and comprehensively quantify ligand binding energies. After evaluation of off-target binding, we report a list of 11 drug-like compounds with improved binding free energy to the target protease in contrast to the cocrystallized peptidomimetic lead compound that suffers from poor pharmacokinetic properties. Furthermore, we identified one potent binder with comparable properties from the natural compound library.

HOMOLOGY MODELING AND SUBSTRATE BINDING STUDY OF HUMAN KYNURENINE AMINOTRANSFERASE III

2012 ◽  
Vol 11 (04) ◽  
pp. 855-870 ◽  
Author(s):  
YU XU ◽  
QING-CHUAN ZHENG ◽  
HONG-XING ZHANG ◽  
CHIA-CHUNG SUN
Keyword(s):  
Homology Modeling ◽  
Active Sites ◽  
Md Simulation ◽  
3D Structure ◽  
Strong Interactions ◽  
Binding Modes ◽  
Kynurenine Aminotransferase ◽  
Dynamics Simulations ◽  
Key Residues ◽  
Good Agreement

Kynurenine aminotransferase III (KAT III) is a novel member of the kynurenine aminotransferase enzyme family. Its active site topology and structure characteristics have not been established. In this study, with extensive computational simulations, including homology modeling and molecular dynamics simulations, a 3D structure model of human KAT III dimer was created and refined. Furthermore, CDOCKER approach was employed to dock two ligands (L-methionine and L-tryptophan) into the active sites of human KAT III dimer and uncover the ligand-binding modes. The complexes were subjected to 5 ns MD simulation, and the results indicate that TYR119 and TRP13 might be the key residues as they have the large contributions to the binding affinity, which is in good agreement with the experimental results. Moreover, another two residues (ASP120 and TYR57) are also found that their strong interactions stabilize the whole system. The structural and biochemical insights obtained from the present study will be helpful for designing the specific inhibitors of human KAT III.

In silico modeling of aspalathin and nothofagin against SGLT2

2015 ◽  
Vol 14 (08) ◽  
pp. 1550056 ◽  
Author(s):  
Wei Liu ◽  
Huanjie Wang ◽  
Fancui Meng
Keyword(s):  
Positive Control ◽  
Binding Energies ◽  
Binding Modes ◽  
In Silico Modeling ◽  
Sodium Dependent ◽  
Sglt2 Inhibition ◽  
Calculation Results ◽  
Dynamics Simulations ◽  
Poor Absorption ◽  
Molecular Docking And Dynamics

Aspalathin and nothofagin are the major dihydrochalcones found in rooibos (Aspalathus linearis), which display anti-diabetic activities, but the mechanism is still unclear. In this paper, hSGLT2 (human sodium dependent glucose co-transporter 2), a target for diabetes mellitus, was built using homology modeling method. Molecular docking and dynamics simulations were carried out on aspalathin, nothofagin and SGLT2 complexes with dapagliflozin as positive control. The results show that both the binding energies and binding modes of aspalathin and nothofagin are similar to dapagliflozin, indicating that either component of rooibos may exhibit anti-diabetic effects through inhibiting SGLT2 receptor. However, the predicted permeability value of aspalathin and nothofagin is low, which may cause poor absorption, resulting in weak SGLT2 inhibition. Calculation results elucidate the possible inhibiting mechanism of aspalathin and nothofagin against SGLT2, and therefore enhance our understanding of anti-diabetic activities of rooibos.

scholarly journals Molecular Docking and Dynamics Investigations for Identifying Potential Inhibitors of the 3-Chymotrypsin-like Protease of SARS-CoV-2: Repurposing of Approved Pyrimidonic Pharmaceuticals for COVID-19 Treatment

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7458
Author(s):  
Amin Osman Elzupir
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Molecular Mechanics ◽  
Surface Area ◽  
Active Sites ◽  
Inhibitory Effect ◽  
Binding Energies ◽  
Poisson Boltzmann ◽  
The Stability ◽  
Dynamics Simulations

This study demonstrates the inhibitory effect of 42 pyrimidonic pharmaceuticals (PPs) on the 3-chymotrypsin-like protease of SARS-CoV-2 (3CLpro) through molecular docking, molecular dynamics simulations, and free binding energies by means of molecular mechanics–Poisson Boltzmann surface area (MM-PBSA) and molecular mechanics–generalized Born surface area (MM-GBSA). Of these tested PPs, 11 drugs approved by the US Food and Drug Administration showed an excellent binding affinity to the catalytic residues of 3CLpro of His41 and Cys145: uracil mustard, cytarabine, floxuridine, trifluridine, stavudine, lamivudine, zalcitabine, telbivudine, tipiracil, citicoline, and uridine triacetate. Their percentage of residues involved in binding at the active sites ranged from 56 to 100, and their binding affinities were in the range from −4.6 ± 0.14 to −7.0 ± 0.19 kcal/mol. The molecular dynamics as determined by a 200 ns simulation run of solvated docked complexes confirmed the stability of PP conformations that bound to the catalytic dyad and the active sites of 3CLpro. The free energy of binding also demonstrates the stability of the PP–3CLpro complexes. Citicoline and uridine triacetate showed free binding energies of −25.53 and −7.07 kcal/mol, respectively. Therefore, I recommend that they be repurposed for the fight against COVID-19, following proper experimental and clinical validation.

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