scholarly journals In silico study on the effects of disulfide bonds in ORF8 of SARS-CoV-2

2021 ◽  
Author(s):  
Yadi Cheng ◽  
Xubiao Peng
Keyword(s):  
Free Energy ◽  
Binding Sites ◽  
In Silico ◽  
Disulfide Bonds ◽  
Immune Modulation ◽  
Binding Free Energy ◽  
Human Leukocyte ◽  
Local Geometry ◽  
Conformational Ensembles ◽  
In Silico Study

The COVID-19 epidemic, caused by virus SARS-CoV-2, has been a pandemic and threatening everyone's health in the past two years. In SARS-CoV-2, the accessory protein ORF8 plays an important role in immune modulation. Here we present an in silico study on the effects of the disulfide bonds in ORF8, including the effects on the structures, the binding sites and free energy when ORF8 binds to the human leukocyte antigen (HLA-A). Using the explicit solvent Molecular Dynamics (MD) simulations, we collect the conformational ensembles on ORF8 with different disulfide bonds reduction schemes. With a new visualization technique on the local geometry, we analyze the effects of the disulfide bonds on the structure of ORF8. We find that the disulfide bonds have large influences on the loop regions of the surface. Moreover, by performing docking between HLA-A and the conformational ensembles of ORF8, we predict the preferred binding sites and find that most of them are little affected by the disulfide bonds. Further, we estimate the binding free energy between HLA-A and ORF8 with different disulfide bonds reductions. In the end, from the comparison with the available experimental results on the epitopes of ORF8, we validated our binding sites prediction. All the above observations may provide inspirations on inhibitor/drug design against ORF8 based on the binding pathway with HLA-A.

scholarly journals Insight on the In Silico Study and Biological Activity Assay of Chalcone-Based 1, 5-Benzothiazepines as Potential Inhibitor for Breast Cancer MCF7

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Neni Frimayanti ◽  
◽  
Marzieh Yaeghoobi ◽  
Ihsan Ikhtiarudin ◽  
Dhea Rizki Wannisyah Putri ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Free Energy ◽  
Biological Activity ◽  
Molecular Dynamic ◽  
In Silico ◽  
Binding Free Energy ◽  
Crystallographic Structure ◽  
Anticancer Activities ◽  
Adme Prediction ◽  
In Silico Study

In silico study was performed to twelve 1,5-benzothiazepine chalcone derivatives with the protein target from the crystallographic structure modeling of the enzyme tyrosine kinase. The objective of this study is to execute and to estimate the biological activity of chalcone-based 1,5-benzothiazepine derivatives as potential inhibitors for breast cancer MCF7. To get insight into potential anticancer activities, molecular docking, molecular dynamic and ADME prediction were performed. Docking results reported that compound MA9 with binding free energy of -11.2 kcal / mol can interact through hydrogen bonds with amino acids Cys788 on 1T46 protein active site. In addition, the lowest binding free energy conformation indicated its stability during molecular dynamic simulation. MA9 is also shown to have drug likeness properties based on ADME prediction. In order to evaluate the modeling outcomes, MTT assay were performed for some of the most and least promising benzologs (i.e., MA1, MA6, MA8 and MA9). As expected, compound MA9 with the best calculated anticancer properties revealed the best inhibition against MCF7cell line in vitro. Thus, this compound was chosen as the reference for the next stage in the drug design.

scholarly journals Structural and Energetic Affinity of Annocatacin B with ND1 Subunit of the Human Mitochondrial Respiratory Complex I as a Potential Inhibitor: An In Silico Comparison Study with the Known Inhibitor Rotenone

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1840
Author(s):  
Camilo Febres-Molina ◽  
Jorge A. Aguilar-Pineda ◽  
Pamela L. Gamero-Begazo ◽  
Haruna L. Barazorda-Ccahuana ◽  
Diego E. Valencia ◽  
...  
Keyword(s):  
Free Energy ◽  
In Silico ◽  
Complex I ◽  
Binding Free Energy ◽  
Biological Activities ◽  
Experimental Studies ◽  
Respiratory Complex ◽  
Mitochondrial Respiratory Complex ◽  
Respiratory Complex I ◽  
Mitochondrial Respiratory

ND1 subunit possesses the majority of the inhibitor binding domain of the human mitochondrial respiratory complex I. This is an attractive target for the search for new inhibitors that seek mitochondrial dysfunction. It is known, from in vitro experiments, that some metabolites from Annona muricata called acetogenins have important biological activities, such as anticancer, antiparasitic, and insecticide. Previous studies propose an inhibitory activity of bovine mitochondrial respiratory complex I by bis-tetrahydrofurans acetogenins such as annocatacin B, however, there are few studies on its inhibitory effect on human mitochondrial respiratory complex I. In this work, we evaluate the in silico molecular and energetic affinity of the annocatacin B molecule with the human ND1 subunit in order to elucidate its potential capacity to be a good inhibitor of this subunit. For this purpose, quantum mechanical optimizations, molecular dynamics simulations and the molecular mechanics/Poisson–Boltzmann surface area (MM/PBSA) analysis were performed. As a control to compare our outcomes, the molecule rotenone, which is a known mitochondrial respiratory complex I inhibitor, was chosen. Our results show that annocatacin B has a greater affinity for the ND1 structure, its size and folding were probably the main characteristics that contributed to stabilize the molecular complex. Furthermore, the MM/PBSA calculations showed a 35% stronger binding free energy compared to the rotenone complex. Detailed analysis of the binding free energy shows that the aliphatic chains of annocatacin B play a key role in molecular coupling by distributing favorable interactions throughout the major part of the ND1 structure. These results are consistent with experimental studies that mention that acetogenins may be good inhibitors of the mitochondrial respiratory complex I.

scholarly journals Elucidating Binding Sites and Affinities of ERα Agonist and Antagonist to Human Alpha-Fetoprotein by in silico Modeling and Point Mutagenesis

2019 ◽  
Author(s):  
Nurbubu T. Moldogazieva ◽  
Daria S. Ostroverkhova ◽  
Nikolai N. Kuzmich ◽  
Vladimir V. Kadochnikov ◽  
Alexander A. Terentiev ◽  
...  
Keyword(s):  
Binding Sites ◽  
In Silico ◽  
Disulfide Bonds ◽  
Electrostatic Interactions ◽  
Molecular Mechanisms ◽  
3D Structure ◽  
Scoring Function ◽  
Alpha Fetoprotein ◽  
Ligand Interaction ◽  
Ligand Interactions

Alpha-fetoprotein (AFP) is a major embryo- and tumor-associated protein capable of binding and transporting variety of hydrophobic ligands including estrogens. AFP has been shown to inhibit estrogen receptor (ER)-positive tumor growth and this can be attributed to its estrogen-binding ability. Despite AFP has long been investigated, its three-dimensional (3D) structure has not been experimentally resolved and molecular mechanisms underlying AFP-ligand interaction remain obscure. In our study we constructed homology-based 3D model of human AFP (HAFP) with the purpose to perform docking of ERα ligands, three agonists (17β-estradiol, estrone and diethylstilbestrol) and three antagonists (tamoxifen, afimoxifene and endoxifen) into the obtained structure. Based on ligand docked scoring function, we identified three putative estrogen- and antiestrogen-binding sites with different ligand binding affinities. Two high-affinity sites were located in (i) a tunnel formed within HAFP subdomains IB and IIA and (ii) opposite side of the molecule in a groove originating from cavity formed between domains I and III, while (iii) the third low-affinity site was found at the bottom of the cavity. 100 ns MD simulation allowed studying their geometries and showed that HAFP-estrogen interactions occur due to van der Waals forces, while both hydrophobic and electrostatic interactions were almost equally involved in HAFP-antiestrogen binding. MM/GBSA rescoring method estimated binding free energies (ΔGbind) and showed that antiestrogens have higher affinities to HAFP as compared to estrogens. We performed in silico point substitutions of amino acid residues to confirm their roles in HAFP-ligand interactions and showed that Thr132, Leu138, His170, Phe172, Ser217, Gln221, His266, His316, Lys453, and Asp478 residues along two disulfide bonds, Cys224-Cys270 and Cys269-Cys277 have key roles in both HAFP-estrogen and HAFP-antiestrogen binding. Data obtained in our study contribute to understanding mechanisms underlying protein-ligand interactions and anti-cancer therapy strategies based on ER-binding ligands.

scholarly journals Three Alkaloids from an Apocynaceae Species, Aspidosperma spruceanum as Antileishmaniasis Agents by In Silico Demo-case Studies

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 983 ◽  
Author(s):  
Diana Morales-Jadán ◽  
José Blanco-Salas ◽  
Trinidad Ruiz-Téllez ◽  
Francisco Centeno
Keyword(s):  
Free Energy ◽  
Active Site ◽  
In Silico ◽  
Binding Free Energy ◽  
New Drugs ◽  
Neglected Tropical Disease ◽  
Physiological Importance ◽  
Promising Tool ◽  
Binding Pockets ◽  
Simulation Results

This paper is focused on demonstrating with a real case that Ethnobotany added to Bioinformatics is a promising tool for new drugs search. It encourages the in silico investigation of “challua kaspi”, a medicinal kichwa Amazonian plant (Aspidosperma spruceanum) against a Neglected Tropical Disease, leishmaniasis. The illness affects over 150 million people especially in subtropical regions, there is no vaccination and conventional treatments are unsatisfactory. In attempts to find potent and safe inhibitors of its etiological agent, Leishmania, we recovered the published traditional knowledge on kichwa antimalarials and selected three A. spruceanum alkaloids, (aspidoalbine, aspidocarpine and tubotaiwine), to evaluate by molecular docking their activity upon five Leishmania targets: DHFR-TS, PTR1, PK, HGPRT and SQS enzymes. Our simulation results suggest that aspidoalbine interacts competitively with the five targets, with a greater affinity for the active site of PTR1 than some physiological ligands. Our virtual data also point to the demonstration of few side effects. The predicted binding free energy has a greater affinity to Leishmania proteins than to their homologous in humans (TS, DHR, PKLR, HGPRT and SQS), and there is no match with binding pockets of physiological importance. Keys for the in silico protocols applied are included in order to offer a standardized method replicable in other cases. Apocynaceae having ethnobotanical use can be virtually tested as molecular antileishmaniasis new drugs.

In-silico Design, ADMET Screening, MM-GBSA Binding Free Energy of Some Novel Isoxazole Substituted 9-Anilinoacridines as HER2 Inhibitors Targeting Breast Cancer

2019 ◽  
Vol 11 (2) ◽  
pp. 118-128 ◽  
Author(s):  
Rajagopal Kalirajan ◽  
Arumugasamy Pandiselvi ◽  
Byran Gowramma ◽  
Pandiyan Balachandran
Keyword(s):  
Breast Cancer ◽  
Free Energy ◽  
In Silico ◽  
Therapeutic Potential ◽  
Binding Free Energy ◽  
Breast Cancers ◽  
Molecular Docking Study ◽  
In Silico Admet

Background: Human Epidermal development factor Receptor-2 (HER2) is a membrane tyrosine kinase which is overexpressed and gene amplified in human breast cancers. HER2 amplification and overexpression have been linked to important tumor cell proliferation and survival pathways for 20% of instances of breast cancer. 9-aminoacridines are significant DNA-intercalating agents because of their antiproliferative properties. Objective: Some novel isoxazole substituted 9-anilinoacridines(1a-z) were designed by in-silico technique for their HER2 inhibitory activity. Docking investigations of compounds 1a-z are performed against HER2 (PDB id-3PP0) by using Schrodinger suit 2016-2. Methods: Molecular docking study for the designed molecules 1a-z are performed by Glide module, in-silico ADMET screening by QikProp module and binding free energy by Prime-MMGBSA module of Schrodinger suit. The binding affinity of designed molecules 1a-z towards HER2 was chosen based on GLIDE score. Results: Many compounds showed good hydrophobic communications and hydrogen bonding associations to hinder HER2. The compounds 1a-z, aside from 1z have significant Glide scores in the scope of - 4.91 to - 10.59 when compared with the standard Ethacridine (- 4.23) and Tamoxifen (- 3.78). The in-silico ADMET properties are inside the suggested about drug likeness. MM-GBSA binding of the most intense inhibitor is positive. Conclusion: The outcomes reveal that this study provides evidence for the consideration of isoxazole substituted 9-aminoacridine derivatives as potential HER2 inhibitors. The compounds, 1s,x,v,a,j,r with significant Glide scores may produce significant anti breast cancer activity and further in vitro and in vivo investigations may prove their therapeutic potential.

scholarly journals Identification of promising drug candidates against Non-Structural Protein 15 (NSP15) from SARS-CoV-2: an in silico assisted drug-repurposing studies

2020 ◽  
Author(s):  
Rameez Jabeer Khan ◽  
Rajat Kumar Jha ◽  
Ekampreet Singh ◽  
Monika Jain ◽  
Gizachew Muluneh Amera ◽  
...  
Keyword(s):  
Free Energy ◽  
In Silico ◽  
Binding Free Energy ◽  
Drug Repurposing ◽  
Md Simulations ◽  
Therapeutic Agents ◽  
Global Dynamics ◽  
Host Immune System ◽  
Structural Protein ◽  
Drug Candidates

<div>The recent COVID-19 pandemic caused by SARS-CoV-2 has recorded a high number of infected people across the globe. The notorious nature of the virus makes it necessary for us to identify promising therapeutic agents in a time-sensitive manner. The current study utilises an <i>in silico</i> based drug repurposing approach to identify potential drug candidates targeting non-structural protein 15 (NSP15), i.e. a uridylate specific endoribonuclease of SARS-CoV-2</div><div>which plays an indispensable role in RNA processing and viral immune evasion from the host immune system. NSP15 was screened against an in-house library of 123 antiviral drugs obtained from the DrugBank database from which three promising drug candidates were identified based on their estimated free energy of binding (<i>ΔG</i>), estimated inhibition constant (<i>Ki</i>), the orientation of drug molecules in the active site and the key interacting residues of</div><div>NSP15. The MD simulations were performed for the selected NSP15-drug complexes along with free protein to mimic on their physiological state. The binding free energies of the selected NSP15-drug complexes were also calculated using the trajectories of MD simulations of NSP15-drug complexes through MM/PBSA (Molecular Mechanics with Poisson-Boltzmann and surface area solvation) approach where NSP15-Simeprevir (-242.559 kJ/mol) and NSP15-Paritaprevir (-149.557 kJ/mol) exhibited the strongest binding affinities. Together with the results of molecular docking, global dynamics, essential dynamics and binding free energy analysis, we propose that Simeprevir and Paritaprevir are promising drug candidates for the inhibition of NSP15 and could act as potential therapeutic agents against SARS-CoV-2.</div>

scholarly journals IN VITRO AND IN SILICO EVALUATION OF XANTHINE OXIDASE INHIBITORY ACTIVITY OF QUERCETIN CONTAINED IN SONCHUS ARVENSIS LEAF EXTRACT

2017 ◽  
Vol 10 (14) ◽  
pp. 50
Author(s):  
Rini Hendriani ◽  
Nursamsiar Nursamsiar ◽  
Ami Tjitraresmi
Keyword(s):  
Free Energy ◽  
Xanthine Oxidase ◽  
Inhibitory Activity ◽  
In Silico ◽  
Leaf Extract ◽  
Binding Free Energy ◽  
Uv Spectrophotometry ◽  
Docking Simulations ◽  
Oxidase Enzyme

Objective: The aim of the present study was to examine the inhibiting effects of quercetin contained in Sonchusarvensis leaf extract on the activity of xanthine oxidase, an essential enzyme for uric acid synthesis.Methods: Activity test was conducted in vitro by measuring the activity of xanthine oxidase using UV spectrophotometry and in silico by determining the interaction of quercetin and allopurinol (as comparation drug) with xanthine oxidase enzyme in terms of hydrogen bonds and binding free energy. Docking simulations were performed by Autodock4.2 package.Results: The active fraction, using the solvent n-hexane, ethyl acetate and water, tested the inhibitory activity of the xanthine oxidase enzyme in vitro obtained respectively IC50 of 263.19, 16.20 and 141.80 μg/ml. Isolates with highest activity identified as quercetin. The xanthine oxidase enzyme inhibitory activity insilico by molecular docking showed quercetin has free energy binding ˗7.71 kcal/mol, more negative than that of allopurinol ˗5.63 kcal/mol.Conclusion: This shows the affinity of quercetin stronger than that of allopurinol; so that it can be predicted that quercetin was more potential to inhibit xanthine oxidase enzyme activity. Thus the extract of the S. arvensis leaves containing the active compound quercetin was a potential use as antihyperuricemia.  

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