scholarly journals Conjugated β-Cyclodextrin Enhances the Affinity of Folic Acid towards FRα: Molecular Dynamics Study

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5304
Author(s):  
Mohammad G. Al-Thiabat ◽  
Amirah Mohd Gazzali ◽  
Noratiqah Mohtar ◽  
Vikneswaran Murugaiyah ◽  
Ezatul Ezleen Kamarulzaman ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Folic Acid ◽  
Root Mean Square ◽  
Active Site ◽  
Md Simulation ◽  
Binding Free Energy ◽  
Cancer Drug ◽  
Radius Of Gyration ◽  
Mean Square ◽  
The Stability

Drug targeting is a progressive area of research with folate receptor alpha (FRα) receiving significant attention as a biological marker in cancer drug delivery. The binding affinity of folic acid (FA) to the FRα active site provides a basis for recognition of FRα. In this study, FA was conjugated to beta-cyclodextrin (βCD) and subjected to in silico analysis (molecular docking and molecular dynamics (MD) simulation (100 ns)) to investigate the affinity and stability for the conjugated system compared to unconjugated and apo systems (ligand free). Docking studies revealed that the conjugated FA bound into the active site of FRα with a docking score (free binding energy < −15 kcal/mol), with a similar binding pose to that of unconjugated FA. Subsequent analyses from molecular dynamics (MD) simulations, root mean square deviation (RMSD), root mean square fluctuation (RMSF), and radius of gyration (Rg) demonstrated that FA and FA–βCDs created more dynamically stable systems with FRα than the apo-FRα system. All systems reached equilibrium with stable RMSD values ranging from 1.9–2.4 Å and the average residual fluctuation values of the FRα backbone atoms for all residues (except for terminal residues ARG8, THR9, THR214, and LEU215) were less than 2.1 Å with a consistent Rg value of around 16.8 Å throughout the MD simulation time (0–100 ns). The conjugation with βCD improved the stability and decreased the mobility of all the residues (except residues 149–151) compared to FA–FRα and apo-FRα systems. Further analysis of H-bonds, binding free energy (MM-PBSA), and per residue decomposition energy revealed that besides APS81, residues HIS20, TRP102, HIS135, TRP138, TRP140, and TRP171 were shown to have more favourable energy contributions in the holo systems than in the apo-FRα system, and these residues might have a direct role in increasing the stability of holo systems.

Design of potential IKK-β inhibitors using molecular docking and molecular dynamics techniques for their anti-cancer potential

2020 ◽  
Vol 16 ◽  
Author(s):  
Salam Pradeep Singh ◽  
Iftikar Hussain ◽  
Bolin Kumar Konwar ◽  
Ramesh Chandra Deka ◽  
Chingakham Brajakishor Singh
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Md Simulation ◽  
Inflammatory Diseases ◽  
Binding Free Energy ◽  
Anti Cancer ◽  
Dietary Phytochemicals ◽  
Toxicity Analysis ◽  
The Stability ◽  
Stable Trajectory

Aim and Objective: To evaluate a set of seventy phytochemicals for their potential ability to bind the inhibitor of nuclear factor kappaB kinase beta (IKK-β) which is a prime target for cancer and inflammatory diseases. Materials and Methods: Seventy phytochemicals were screened against IKK-β enzyme using DFT-based molecular docking technique and the top docking hits were carried forward for molecular dynamics (MD) simulation protocols. The adme-toxicity analysis was also carried out for the top docking hits. Results: Sesamin, matairesinol and resveratrol were found to be the top docking hits with a total score of -413 kJ/mol, -398.11 kJ/mol and 266.73 kJ/mol respectively. Glu100 and Gly102 were found to be the most common interacting residues. The result from MD simulation observed a stable trajectory with a binding free energy of -107.62 kJ/mol for matairesinol, -120.37 kJ/mol for sesamin and -40.56 kJ/mol for resveratrol. The DFT calculation revealed the stability of the compounds. The ADME-Toxicity prediction observed that these compounds fall within the permissible area of Boiled-Egg and it does not violate any rule for pharmacological criteria, drug-likeness etc. Conclusion: The study interprets that dietary phytochemicals are potent inhibitors of IKK-β enzyme with favourable binding affinity and less toxic effects. In fact, there is a gradual rise in the use of plant-derived molecules because of its lesser side effects compared to chemotherapy. The study has also provided an insight by which the phytochemicals inhibited the IKK-β enzyme. The investigation would also provide in understanding the inhibitory mode of certain dietary phytochemicals in treating cancer.

scholarly journals Luteolin and abyssinone II as potential inhibitors of SARS-CoV-2: an in silico molecular modeling approach in battling the COVID-19 outbreak

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Mohammad Mahfuz Ali Khan Shawan ◽  
Sajal Kumar Halder ◽  
Md. Ashraful Hasan
Keyword(s):  
Molecular Dynamics ◽  
Root Mean Square ◽  
In Silico ◽  
Binding Free Energy ◽  
Biologically Active ◽  
Dynamics Simulation ◽  
Mean Square ◽  
Efficient Treatment ◽  
Target Proteins

Abstract Background At present, the entire world is in a war against COVID-19 pandemic which has gradually led us toward a more compromised “new normal” life. SARS-CoV-2, the pathogenic microorganism liable for the recent COVID-19 outbreak, is extremely contagious in nature resulting in an unusual number of infections and death globally. The lack of clinically proven therapeutic intervention for COVID-19 has dragged the world’s healthcare system into the biggest challenge. Therefore, development of an efficient treatment scheme is now in great demand. Screening of different biologically active plant-based natural compounds could be a useful strategy for combating this pandemic. In the present research, a collection of 43 flavonoids of 7 different classes with previously recorded antiviral activity was evaluated via computational and bioinformatics tools for their impeding capacity against SARS-CoV-2. In silico drug likeness, pharmacophore and Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) profile analysis of the finest ligands were carried out using DataWarrior, DruLiTo and admetSAR programs, respectively. Molecular docking was executed by AutoDock Vina, while molecular dynamics simulation of the target protein–ligand bound complexes was done using nanoscalable molecular dynamics and visual molecular dynamics software package. Finally, the molecular target analysis of the selected ligands within Homo sapiens was conducted with SwissTargetPredcition web server. Results Out of the forty-three flavonoids, luteolin and abyssinone II were found to develop successful docked complex within the binding sites of target proteins in terms of lowest binding free energy and inhibition constant. The root mean square deviation and root mean square fluctuation values of the docked complex displayed stable interaction and efficient binding between the ligands and target proteins. Both of the flavonoids were found to be safe for human use and possessed good drug likeness properties and target accuracy. Conclusions Conclusively, the current study proposes that luteolin and abyssinone II might act as potential therapeutic candidates for SARS-CoV-2 infection. In vivo and in vitro experiments, however, should be taken under consideration to determine the efficiency and to demonstrate the mechanism of action.

scholarly journals Investigating the role of N-terminal domain in phosphodiesterase 4B-inhibition by molecular dynamics simulation

2020 ◽  
Author(s):  
Vidushi Sharma ◽  
Sharad Wakode
Keyword(s):  
Ligand Binding ◽  
Root Mean Square ◽  
Active Site ◽  
Binding Pocket ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Mean Square ◽  
Sequence Identity ◽  
Terminal Domain ◽  
Phosphodiesterase 4B

AbstractPhosphodiesterase 4B (PDE4B) is a potential therapeutic target for the inflammatory respiratory diseases such as congestive obstructive pulmonary disease (COPD) and asthma. The sequence identity of ∼88% with its isoform PDE4D is the key barrier in developing selective PDE4B inhibitors which may help to overcome associated side effects. Despite high sequence identity, both isoforms differ in few residues present in N-terminal (UCR2) and C-terminal (CR3) involved in catalytic site formation. Previously, we designed and tested specific PDE4B inhibitors considering N-terminal residues as a part of the catalytic cavity. In continuation, current work thoroughly presents an MD simulation-based analysis of N-terminal residues and their role in ligand binding. The various parameters viz. root mean square deviation (RMSD), radius of gyration (Rg), root mean square fluctuation (RMSF), principal component analysis (PCA), dynamical cross-correlation matrix (DCCM) analysis, secondary structure analysis, and residue interaction mapping were investigated to establish rational. Results showed that UCR2 reduced RMSF values for the metal binding pocket (31.5±11 to 13.12±6 Å2) and the substrate-binding pocket (38.8±32 to 17.3±11 Å2). UCR2 enhanced anti-correlated motion at the active site region that led to the improved ligand-binding affinity of PDE4B from −24.57±3 to −35.54±2 kcal/mol. Further, the atomic-level analysis indicated that T-pi and π-π interactions between inhibitors and residues are vital forces that regulate inhibitor association to PDE4B with high affinity. In conclusion, UCR2, the N-terminal domain, embraces the dynamics of PDE4B active site and stabilizes PDE4B inhibitor interactions. Therefore the N-terminal domain needs to be included by designing next-generation, selective PDE4B-inhibitors as potential anti-inflammatory drugs.

MOLECULAR DOCKING AND MOLECULAR DYNAMICS STUDIES OF THE INTERACTION BETWEEN COUMARIN-NEUROTRANSMITTER DERIVATIVES AND CARBONIC ANHYDRASE IX

2021 ◽  
Author(s):  
Dušan Dimić ◽  
◽  
Dejan Milenković ◽  
Edina Avdović ◽  
Goran Kaluđerović ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Carbonic Anhydrase ◽  
Root Mean Square ◽  
Binding Energies ◽  
Intramolecular Interactions ◽  
Biologically Active ◽  
Radius Of Gyration ◽  
Mean Square ◽  
Native Ligand

Novel biologically active compounds can be obtained by the structural modification of coumarins. In this contribution, five new derivatives of 4-hydroxycoumarin with tyramine, octopamine, norepinephrine, 3-methoxytyramine, and dopamine were obtained. Their structures were optimized based on the previously obtained crystal structure of the 4-hydroxycoumarin-dopamine derivative. The special emphasis was put on the effect of various substituents on the structure of obtained compounds and intramolecular interactions governing the stability. To investigate their possible antitumor activity, molecular docking and molecular dynamics simulations were performed with Carbonic anhydrase, a prognostic factor in several cancers, and compared to the native ligand, 5-acetamido-1,3,4-thiadiazole- 2-sulfonamide. The results have shown that all of the coumarin-neurotransmitter derivatives bind to the active pocket of protein with the binding energies higher than for the native ligand. The main contributions to the binding energies were discussed. The Root Mean Square Deviation (RMSD), Root Mean Square Fluctuation (RMSF), and Radius of gyration (Rg), as results of MD simulations, were used to predict the activity of compounds towards chosen protein. The highest MD binding energies were obtained for the derivatives with dopamine and 3-methoxytyramine, with the van der Waals interaction and hydrogen bonds being the most important contributors.

scholarly journals Efficacy of Phytochemicals Derived from Avicennia officinalis for the Management of COVID-19: A Combined In Silico and Biochemical Study

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2210
Author(s):  
Shafi Mahmud ◽  
Gobindo Kumar Paul ◽  
Mirola Afroze ◽  
Shirmin Islam ◽  
Swagota Briti Ray Gupt ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Antioxidant Activities ◽  
Binding Free Energy ◽  
Healthcare Management ◽  
Dynamics Simulation ◽  
Solvent Accessible Surface Area ◽  
Radius Of Gyration ◽  
Mean Square ◽  
Main Protease ◽  
Avicennia Officinalis

The recent coronavirus disease 2019 (COVID-19) pandemic is a global threat for healthcare management and the economic system, and effective treatments against the pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus responsible for this disease have not yet progressed beyond the developmental phases. As drug refinement and vaccine progression require enormously broad investments of time, alternative strategies are urgently needed. In this study, we examined phytochemicals extracted from Avicennia officinalis and evaluated their potential effects against the main protease of SARS-CoV-2. The antioxidant activities of A. officinalis leaf and fruit extracts at 150 µg/mL were 95.97% and 92.48%, respectively. Furthermore, both extracts displayed low cytotoxicity levels against Artemia salina. The gas chromatography–mass spectroscopy analysis confirmed the identifies of 75 phytochemicals from both extracts, and four potent compounds, triacontane, hexacosane, methyl linoleate, and methyl palminoleate, had binding free energy values of −6.75, −6.7, −6.3, and −6.3 Kcal/mol, respectively, in complexes with the SARS-CoV-2 main protease. The active residues Cys145, Met165, Glu166, Gln189, and Arg188 in the main protease formed non-bonded interactions with the screened compounds. The root-mean-square difference (RMSD), root-mean-square fluctuations (RMSF), radius of gyration (Rg), solvent-accessible surface area (SASA), and hydrogen bond data from a molecular dynamics simulation study confirmed the docked complexes′ binding rigidity in the atomistic simulated environment. However, this study′s findings require in vitro and in vivo validation to ensure the possible inhibitory effects and pharmacological efficacy of the identified compounds.

scholarly journals Heterocyclic Substitutions Greatly Improve Affinity and Stability of Folic Acid towards FRα. an In Silico Insight

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1079
Author(s):  
Mohammad G. Al-Thiabat ◽  
Fadi G. Saqallah ◽  
Amirah Mohd Gazzali ◽  
Noratiqah Mohtar ◽  
Beow Keat Yap ◽  
...  
Keyword(s):  
Folic Acid ◽  
Binding Affinity ◽  
Root Mean Square ◽  
Active Site ◽  
Hydrophobic Interactions ◽  
Md Simulations ◽  
The Body ◽  
Electrostatic Energy ◽  
Epithelial Tissue ◽  
Mean Square

Folate receptor alpha (FRα) is known as a biological marker for many cancers due to its overexpression in cancerous epithelial tissue. The folic acid (FA) binding affinity to the FRα active site provides a basis for designing more specific targets for FRα. Heterocyclic rings have been shown to interact with many receptors and are important to the metabolism and biological processes within the body. Nineteen FA analogs with substitution with various heterocyclic rings were designed to have higher affinity toward FRα. Molecular docking was used to study the binding affinity of designed analogs compared to FA, methotrexate (MTX), and pemetrexed (PTX). Out of 19 FA analogs, analogs with a tetrazole ring (FOL03) and benzothiophene ring (FOL08) showed the most negative binding energy and were able to interact with ASP81 and SER174 through hydrogen bonds and hydrophobic interactions with amino acids of the active site. Hence, 100 ns molecular dynamics (MD) simulations were carried out for FOL03, FOL08 compared to FA, MTX, and PTX. The root mean square deviation (RMSD) and root mean square fluctuation (RMSF) of FOL03 and FOL08 showed an apparent convergence similar to that of FA, and both of them entered the binding pocket (active site) from the pteridine part, while the glutamic part was stuck at the FRα pocket entrance during the MD simulations. Molecular mechanics Poisson-Boltzmann surface accessible (MM-PBSA) and H-bond analysis revealed that FOL03 and FOL08 created more negative free binding and electrostatic energy compared to FA and PTX, and both formed stronger H-bond interactions with ASP81 than FA with excellent H-bond profiles that led them to become bound tightly in the pocket. In addition, pocket volume calculations showed that the volumes of active site for FOL03 and FOL08 inside the FRα pocket were smaller than the FA–FRα system, indicating strong interactions between the protein active site residues with these new FA analogs compared to FA during the MD simulations.

scholarly journals Molecular Dynamics Simulation of Cholera Toxin A-1 Polypeptide

2016 ◽  
Vol 14 (1) ◽  
pp. 188-196 ◽  
Author(s):  
Syed Lal Badshah ◽  
Abdul Naeem Khan ◽  
Yahia Nasser Mabkhot
Keyword(s):  
Molecular Dynamics ◽  
Secondary Structure ◽  
Cholera Toxin ◽  
Root Mean Square ◽  
Host Cells ◽  
Dynamics Simulation ◽  
Solvent Accessible Surface Area ◽  
Radius Of Gyration ◽  
Mean Square ◽  
Toxin A

AbstractA molecular dynamics (MD) simulation study of the enzymatic portion of cholera toxin; cholera toxin A-1 polypeptide (CTA1) was performed at 283, 310 and 323 K. From total energy analysis it was observed that this toxin is stable thermodynamically and these outcomes were likewise confirmed by root mean square deviations (RMSD) investigations. The Cα root mean square fluctuation (RMSF) examinations revealed that there are a number of residues inside CTA1, which can be used as target for designing and synthesizing inhibitory drugs, in order to inactivate cholera toxin inside the human body. The fluctuations in the radius of gyration and hydrogen bonding in CTA1 proved that protein unfolding and refolding were normal routine phenomena in its structure at all temperatures. Solvent accessible surface area study identified the hydrophilic nature of the CTA1, and due to this property it can be a potential biological weapon. The structural identification (STRIDE) algorithm for proteins was successfully used to determine the partially disordered secondary structure of CTA1. On account of this partially disordered secondary structure, it can easily deceive the proteolytic enzymes of the endoplasmic reticulum of host cells.

scholarly journals Identification of Phosphatidylinositol 3-kinase δ (PI3Kδ) Inhibitor: Pharmacophore-based Virtual Screening and Molecular Dynamics Simulation

2020 ◽  
Vol 20 (5) ◽  
pp. 1070
Author(s):  
Muhammad Arba ◽  
Malindo Sufriadin ◽  
Daryono Hadi Tjahjono
Keyword(s):  
Molecular Dynamics ◽  
Root Mean Square ◽  
Conformational Changes ◽  
Binding Free Energy ◽  
Pharmacophore Model ◽  
Dynamics Simulation ◽  
Mean Square ◽  
Phosphatidylinositol 3 Kinase ◽  
Pharmacophore Modelling ◽  
Phosphatidylinositol 3

Phosphatidylinositol 3-kinase δ (PI3Kδ) is a validated drug target for the treatment of cancer. The present study aims to search for new inhibitors of PI3Kδ by employing pharmacophore modelling using LigandScout Advanced 4.3 software. The three hydrogen bond acceptors and two hydrophobic features were proposed as a pharmacophore model using LASW1976 structure. The model was then validated using the Area Under Curve (AUC) of Receiver Operating Characteristic (ROC) and GH score. It was used to screen new molecules in the ZINC database, which resulted in 599 hits. All 599 hits were then docked into PI3Kδ protein, and five best hits were submitted to 50 ns molecular dynamics simulations. Each hit complexed with PI3Kδ underwent minor conformational changes as indicated by the values of Root Mean Square Deviation (RMSD) and Root Mean Square Fluctuation (RMSF). Furthermore, prediction of the binding free energy using Molecular Mechanics-Poisson Boltzmann Surface Area (MM-PBSA) method showed that five hits, i.e., Lig25/ZINC253496376, Lig682/ZINC98047241, Lig449/ZINC85878047, Lig554/ZINC253389510, and Lig199/ZINC12638303, had lower binding energy compared to LASW1976. This result indicated their potentials as new inhibitors of PI3Kδ.

Study on the Stress Relaxation of Polychloroprene Rubber by Molecular Dynamics Simulation at Different Temperature

2012 ◽  
Vol 532-533 ◽  
pp. 311-315 ◽  
Author(s):  
Yue Kai Gao ◽  
Xue Jia Ding ◽  
Tao Hu ◽  
Yi Li ◽  
Si Zhu Wu
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Stress Relaxation ◽  
Md Simulation ◽  
Dynamics Simulation ◽  
Gyration Radius ◽  
Radius Of Gyration ◽  
Mean Square ◽  
Relaxation Experiment ◽  
Different Temperatures

In this study, molecular dynamics (MD) simulation has been employed to investigate the distribution function of gyration radius under different temperatures. The structure of chloroprene rubber (CR) was constructed and the circles of energy minimization were applied. The fitting functions of normal stress with time under different pressures were obtained. Compression stress relaxation experiment of different temperatures was also conducted. Comparing with the coefficient of stress relaxation from the experiment, it was found that the theoretical stress relaxation results were similar to the experimental data. The results indicated that the mean-square radius of gyration decreased with reduction of temperature, which corresponded to the typical viscoelasticity stress relaxation behaviors of polymers. It is confirmed that the variation of mean-square radius can be used to quantitatively describe the stress relaxation of rubber system and a good agreement between the theoretical curves with the experimental data can be obtained from MD simulation.

scholarly journals Engineering the Enantioselectivity and Thermostability of a (+)-γ-Lactamase from Microbacterium hydrocarbonoxydans for Kinetic Resolution of Vince Lactam (2-Azabicyclo[2.2.1]hept-5-en-3-one)

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Shuaihua Gao ◽  
Shaozhou Zhu ◽  
Rong Huang ◽  
Hongxia Li ◽  
Hao Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Protein Engineering ◽  
Root Mean Square ◽  
Active Site ◽  
Kinetic Resolution ◽  
Mean Square ◽  
Content Type ◽  
Enantiomerically Pure ◽  
Mean Square Fluctuation ◽  
Microbacterium Hydrocarbonoxydans

ABSTRACT To produce promising biocatalysts, natural enzymes often need to be engineered to increase their catalytic performance. In this study, the enantioselectivity and thermostability of a (+)-γ-lactamase from Microbacterium hydrocarbonoxydans as the catalyst in the kinetic resolution of Vince lactam (2-azabicyclo[2.2.1]hept-5-en-3-one) were improved. Enantiomerically pure (−)-Vince lactam is the key synthon in the synthesis of antiviral drugs, such as carbovir and abacavir, which are used to fight against HIV and hepatitis B virus. The work was initialized by using the combinatorial active-site saturation test strategy to engineer the enantioselectivity of the enzyme. The approach resulted in two mutants, Val54Ser and Val54Leu, which catalyzed the hydrolysis of Vince lactam to give (−)-Vince lactam, with 99.2% (enantiomeric ratio [E] > 200) enantiomeric excess (ee) and 99.5% ee (E > 200), respectively. To improve the thermostability of the enzyme, 11 residues with high temperature factors (B-factors) calculated by B-FITTER or high root mean square fluctuation (RMSF) values from the molecular dynamics simulation were selected. Six mutants with increased thermostability were obtained. Finally, the mutants generated with improved enantioselectivity and mutants evolved for enhanced thermostability were combined. Several variants showing (+)-selectivity (E value > 200) and improved thermostability were observed. These engineered enzymes are good candidates to serve as enantioselective catalysts for the preparation of enantiomerically pure Vince lactam. IMPORTANCE Enzymatic kinetic resolution of the racemic Vince lactam using (+)-γ-lactamase is the most often utilized means of resolving the enantiomers for the preparation of carbocyclic nucleoside compounds. The efficiency of the native enzymes could be improved by using protein engineering methods, such as directed evolution and rational design. In our study, two properties (enantioselectivity and thermostability) of a γ-lactamase identified from Microbacterium hydrocarbonoxydans were tackled using a semirational design. The protein engineering was initialized by combinatorial active-site saturation test to improve the enantioselectivity. At the same time, two strategies were applied to identify mutation candidates to enhance the thermostability based on calculations from both a static (B-FITTER based on the crystal structure) and a dynamic (root mean square fluctuation [RMSF] values based on molecular dynamics simulations) way. After combining the mutants, we successfully obtained the final mutants showing better properties in both properties. The engineered (+)-lactamase could be a candidate for the preparation of (−)-Vince lactam.

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