Molecular Docking of the Terpenes in Gorgonian Corals to COX-2 and iNOS Enzymes as Anti-Inflammatory

Background: The inflammatory pathway is induced by cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) enzymes, so it requires the development of its inhibitors, such as nonsteroidal anti-inflammatory drugs (NSAIDs), but they have side effects. Therefore, the discovery and development of natural medicine as a lead compound are needed. The gorgonian corals have been reported to contain cyclic diterpenes with anti-inflammatory activities. The specific anti-inflammatory inhibitor potential has not been reported regarding these secondary metabolites, whether in COX-2 or iNOS. Thus, the in silico method is the right alternative. Objective: This study aimed to determine the potency of fifteen terpenes of the various gorgonian corals to COX-2 and iNOS enzymes as an anti-inflammatory Methods: Molecular docking was performed using ChemDraw Ultra 12.0, Chem3D Pro 12.0, Biovia Discovery Studio 2016 Client®, Autodock Tools 4.2, prediction pharmacokinetics (Pre-ADMET), and oral administration (Lipinski rule of five). Results: Potential terpenes based on ΔG (kcal/mol) and Ki (nM) to COX-2 were gyrosanol B (-10,32; 27,15), gyrosanol A (-10,20; 33,57), echinolabdane A (-9,81; 64,76). Only nine terpenes were specific to COX-2 active sites, while for iNOS were palmonine F (-7.76; 2070), briarenol C (-7.55; 2910), and all test compounds binding to the iNOS active sites. Pre-ADMET prediction obtained that HIA was very excellent (70–100%), Caco-2 had moderate permeability (4–70 nm sec-1), and PPB had strong binding (> 90%). Eight terpenes qualified for the Lipinski rule of five. Conclusion: NOS was a specific target for terpenes based on the free energy of binding (ΔG).

Molecular Docking and Virtual Screening of an Influenza Virus Inhibitor That Disrupts Protein–Protein Interactions

Influenza is an acute respiratory infection caused by the influenza virus, but few drugs are available for its treatment. Consequently, researchers have been engaged in efforts to discover new antiviral mechanisms that can lay the foundation for novel anti-influenza drugs. The viral RNA-dependent RNA polymerase (RdRp) is an enzyme that plays an indispensable role in the viral infection process, which is directly linked to the survival of the virus. Methods of inhibiting PB1–PB2 (basic polymerase 1–basic polymerase 2) interactions, which are a key part of RdRp enzyme activity, are integral in the design of novel antiviral drugs, a specific PB1–PB2 interactions inhibitor has not been reported. We have screened Enamine’s database and conducted a parallel screening of multiple docking schemes, followed by simulations of molecular dynamics to determine the structure of a stable ligand—PB1 complex. We also calculated the free energy of binding between the screened compounds and PB1 protein. Ultimately, we screened and identified a potential PB1–PB2 inhibitor using the ADMET prediction model.

Intriguing Role of Water in Plant Hormone Perception

Plant hormones are small molecules that regulate plant growth, development, and responses to biotic and abiotic stresses. Plant hormones are specifically recognized by the binding site of their receptors. In this work, we investigated the role of water displacement and reorganization at the binding site of plant receptors on the binding of eight classes of phytohormones (auxin, jasmonate, gibberellin, strigolactone, brassinosteroid, cytokinin, salicylic acid, and abscisic acid) using extensive molecular dynamics simulations and inhomogeneous solvation theory. Our findings demonstrated that displacement of water molecules by phytohormones contributes to free energy of binding via entropy gain and is associated with free energy barriers. Also, our results have shown that displacement of unfavorable water molecules in the binding site can be exploited in rational agrochemical design. Overall, this study uncov- ers the role of water molecules in plant hormone perception, which creates new avenues for agrochemical design to target plant growth and development.

Lysozyme–AuNPs Interactions: Determination of Binding Free Energy

Investigation and optimization of lysozyme (Lys) adsorption onto gold nanoparticles, AuNPs, were carried out. The purpose of this study is to determine the magnitude of the AuNPs–lysozyme interaction in aqueous media by simple spectrophotometric means, and to obtain the free energy of binding of the system for the first time. In order to explore the possibilities of gold nanoparticles for sensing lysozyme in aqueous media, the stability of the samples and the influence of the gold and nanoparticle concentrations in the detection limit were studied. ζ potential measurements and the shift of the surface plasmon band showed a state of saturation with an average number of 55 Lys per gold nanoparticle. Lysozyme–AuNPs interactions induce aggregation of citrate-stabilized AuNPs at low concentrations by neutering the negative charges of citrate anions; from those aggregation data, the magnitude of the interactions has been measured by using Benesi–Hildebrand plots. However, at higher protein concentrations aggregation has been found to decrease. Although the nanocluster morphology remains unchanged in the presence of Lys, slight conformational changes of the protein occur. The influence of the size of the nanoclusters was also investigated for 5, 10, and 20 nm AuNPs, and 10 nm AuNPs was found the most appropriate.

NUMBER OF RUNS VARIATIONS ON AUTODOCK 4 DO NOT HAVE A SIGNIFICANT EFFECT ON RMSD FROM DOCKING RESULTS

The aim. The number of runs in the docking process with AutoDock 4 is known to play an important role in the validity of the results obtained. The greater the number of runs it is often associated with the more valid docking results. However, it is not known exactly how the most ideal runs in the docking process with AutoDock 4. This study aims to determine the effect of the number of runs docking processes with AutoDock 4 on the validity of the docking results.Materials and methods. The method used is the redocking process with AutoDock 4.2.6. The receptor used is an estrogen receptor with ligand reference estradiol (PDB ID 1GWR). Variations were made on the number of runs from 10 to 100 in multiples of 10. The parameters observed were RMSD, free energy of binding, inhibition constants, amino acid residues, and the number of hydrogen bonds.Results. All experiments produce identical bond free energy, where the maximum difference in inhibition constant is only 0.06 nM. The lowest RMSD is indicated by the number of runs of 60, with a RMSD value of 0.942. There is no linear relationship between the number of runs and RMSD, with R in the linear equation of 0.4607.Conclusion. Overall, the number of runs does not show a significant contribution to the validity of the results of docking with AutoDock 4. However, these results have only been proven with the receptors used.

VIRTUAL TARGET CONSTRUCTION FOR STRUCTURE-BASED SCREENING IN THE DISCOVERY OF HISTAMINE H2 RECEPTOR LIGANDS

Objective: This study aimed to develop validated targets to be employed in structure-based virtual screening (SBVS) to discover ligands for the human histamine H2 receptor (hHRH2). Methods: The virtual targets construction was initiated by homology modeling with the reference compound ranitidine as the ligand followed by 100 ns molecular dynamics (MD) simulations. During MD simulations, the snapshot with the lowest value of the free energy of binding was selected for further validation by re-docking simulations. All simulations were performed in YASARA-Structure. Results: The research presented here resulted in one validated target for the SBVS. Additionally, by employing a clustering module in MD simulations analysis in YASARA-Structure, more than ten different virtual targets are also available for further uses. Conclusion: The virtual targets resulted in this research offer possibilities to construct valid SBVS protocols to identify ligands for the hHRH2.

Molecular docking approach to elucidate metabolic detoxification pathway of polycyclic aromatic hydrocarbons

This study assessed the molecular interactions of (±)-anti-and-syn- dibenzo[a,l]pyrene-11,12-diol-13,14-epoxide (DBPDE), 7,12- dimethylbenz[a]anthracene-3,4-diol-1,2-epoxide (DMBADE), N2- hydroxylated-PhIP(N2-OH-PhIP), (±)-anti-and-syn-benzo[a]pyrene-7,8-diol- 9,10-epoxide (BPDE) with various Glutathione S-transferase (GST) and N- acetyltransferase (NAT) isozymes. Our in-silico data revealed that GSTP1 (- 8.83 kcal/mol), showing more plausible binding as compared to GSTM1 (-8.74 kcal/mol) and GSTA1 (ΔG: -8.03 kcal/mol) against (-)-anti-DBPDE and (+)- syn-DBPDE. We also investigated the involvement of GST and NAT isozymes in the conjugation of DMBADE andN2-OH-PhIP as a control despite their preferred routes sulfonation and glucuronidation for detoxification. The findings exhibited feeble binding of different classes of GSTs with metabolites of DMBA and PhIP, as highlighted by their free energy of binding. The enzymatic activity of GSTM1 against the most potent diol-epoxide of benzo[a]pyrene (BP), (+)-anti-BPDE, and (+)-syn-BPDE followed by GSTP1 and GSTA1 has well documented. In addition, these findings provide new perspectives for most probable mechanistic details of the detoxification pathway of PAHs and xenobiotics useful in combination therapy for future ligand-based drug discovery and development.

A New Proposed Mechanism of some Known Drugs Targeting the SARS-CoV-2 Spike Glycoprotein Using Molecular Docking

COVID-19 is caused by the novel enveloped beta-coronavirus with a genomic RNA closely related to severe acute respiratory syndrome-corona virus (SARS-CoV) and is named coronavirus 2 (SARS-CoV-2). In this study, six synthetic drugs were specifically docked against the RBD. Most of the six compounds were observed to fit nicely with specific noncovalent interactions. Oseltamivir was found to be the most strongly interacting with the RBD, exhibiting high values of full fitness and low free energy of binding. It formed multiple noncovalent bonds in the region of the active site. Hydroxychloroquine also demonstrated high binding affinity in the solvent accessibility state and fit nicely into the S-protein's active pocket. The results revealed that these compounds could be potent inhibitors of S-protein that could, to some extent, block its interaction with ACE-2. It is obvious from the 3D structure of SARS-CoV-2 spike protein was changed with the interaction of different drugs, which led to the unsuitability to bind ACE2 receptor. Hence, laboratory studies elucidating the action of these compounds on SARS-CoV-2 are warranted for clinical assessments. Chloroquine, hydroxychloroquine, and oseltamivir interacted well with the receptor-binding domain of S-protein via noncovalent interactions and were recommended as excellent candidates for COVID-19.

MOLECULAR DOCKING ANALYSES OF SOME CYCLOHEXADIENE DERIVATIVES

The molecular docking study was performed with aim to examine the inhibitory potency of two selected cyclohexadiene derivatives (cis-(1S)-3-Fluoro-3,5-cyclohexadiene-1,2-diol (1), and 1,1′-(3,5-Cyclohexadiene-1,3-diyl)dibenzene (2)). The inhibitory potency of compounds 1 and 2 was investigated toward Urokinase Type Plasminogen Activator (uPa). For this purpose AutoDock 4.0 software was used. The thermodynamic parameters achieved from molecular docking simulations, free energy of binding (ΔGbind) and inhibition constant (Ki), are analyzed and discussed. The compound 2 shows better inhibitory potency through uPa, than compound 1.

Docking studies with multiple molecular targets associated with SARSCoV-2 for drug repurposing

Background: The current pandemic outbreak of COVID-19 due to viral infections by SARS-CoV-2 is now become associated with severe commotion on global healthcare and economy. Objective: In this extreme situation when vaccine or effective new drugs against COVID-19 are not available, the only quick and feasible therapeutic alternative would be the drug repurposing approach. Method: In the present work, in silico screening of some antiviral and antiprotozoal drugs was performed based on docking using Autodock. Results: Two known antiviral drugs sorivudine and noricumazole B are predicted to bind to the active site of the viral proteases namely cysteine like protease or 3CL protease (3CLpro) and papain like protease (PLpro) respectively with a highly favorable free energy of binding. Further, the promising molecules were subjected for checking their activity on other molecular targets in SARS-CoV-2 like spike protein S1, RNA dependent RNA polymerase (RdRp) and angiotensin converting enzyme 2 (ACE2) receptor. But the compounds were found non-effective on rest other molecular targets. Conclusion: Sorivudine alone or a combination of sorivudine and noricumazole B may be administered to impede viral replication though the predicted drug likeliness of noricumazole B is not very much satisfactory. These observations are solely based on the results from blind docking with protein molecules and that need to be further corroborated with experimental results.