Molecular Simulation Approach Research Articles

Molecular modeling and simulation approaches to characterize potential molecular targets for burdock inulin to instigate protection against autoimmune diseases.

In the current study, we utilized molecular modeling and simulation approaches to define putative potential molecular targets for Burdock Inulin, including inflammatory proteins such as iNOS, COX-2, TNF-alpha, IL-6, and IL-1β. Molecular docking results revealed potential interactions and good binding affinity for these targets; however, IL-1β, COX-2, and iNOS were identified as the best targets for Inulin. Molecular simulation-based stability assessment demonstrated that inulin could primarily target iNOS and may also supplementarily target COX-2 and IL-1β during DSS-induced colitis to reduce the role of these inflammatory mechanisms. Furthermore, residual flexibility, hydrogen bonding, and structural packing were reported with uniform trajectories, showing no significant perturbation throughout the simulation. The protein motions within the simulation trajectories were clustered using principal component analysis (PCA). The IL-1β-Inulin complex, approximately 70% of the total motion was attributed to the first three eigenvectors, while the remaining motion was contributed by the remaining eigenvectors. In contrast, for the COX2-Inulin complex, 75% of the total motion was attributed to the eigenvectors. Furthermore, in the iNOS-Inulin complex, the first three eigenvectors contributed to 60% of the total motion. Furthermore, the iNOS-Inulin complex contributed 60% to the total motion through the first three eigenvectors. To explore thermodynamically favorable changes upon mutation, motion mode analysis was carried out. The Free Energy Landscape (FEL) results demonstrated that the IL-1β-Inulin achieved a single conformation with the lowest energy, while COX2-Inulin and iNOS-Inulin exhibited two lowest-energy conformations each. IL-1β-Inulin and COX2-Inulin displayed total binding free energies of - 27.76kcal/mol and - 37.78kcal/mol, respectively, while iNOS-Inulin demonstrated the best binding free energy results at - 45.89kcal/mol. This indicates a stronger pharmacological potential of iNOS than the other two complexes. Thus, further experiments are needed to use inulin to target iNOS and reduce DSS-induced colitis and other autoimmune diseases.

Disulfide/α-Amide-Bridged Doxorubicin Dimeric Prodrug: Effect of Aggregation Structures on pH/GSH Dual-Triggered Drug Release.

Disulfide bonding has attracted intense interest in the tumor intracellular microenvironment-activated drug delivery systems (DDSs) in the last decades. Although various molecular structures of redox-responsive disulfide-containing DDSs have been developed, no investigation was reported on the effect of aggregation structures. Here, the effect of aggregation structures on pH/GSH dual-triggered drug release was investigated with the simplest pH/GSH dual-triggered doxorubicin-based drug self-delivery system (DSDS), the disulfide/α-amide-bridged doxorubicin dimeric prodrug (DDOX), as a model. By fast precipitation or slow self-assembly, DDOX nanoparticles were obtained. With similar diameters, they exhibited different pH/GSH dual-triggered drug releases, demonstrating the effect of aggregation structures. The π-π stacking in different degrees was revealed by the UV-vis, fluorescence, and BET analysis of the DDOX nanoparticles. The effect of the π-π stacking between the dimeric prodrug and its activated products on drug release was also explored with the molecular simulation approach. The finding opens new ideas in the design of high-performance DDSs for future precise tumor treatment.

Abrogation of ORF8–IRF3 binding interface with Carbon nanotube derivatives to rescue the host immune system against SARS-CoV-2 by using molecular screening and simulation approaches

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has led to over six million deaths worldwide. In human immune system, the type 1 interferon (IFN) pathway plays a crucial role in fighting viral infections. However, the ORF8 protein of the virus evade the immune system by interacting with IRF3, hindering its nuclear translocation and consequently downregulate the type I IFN signaling pathway. To block the binding of ORF8–IRF3 and inhibit viral pathogenesis a quick discovery of an inhibitor molecule is needed. Therefore, in the present study, the interface between the ORF8 and IRF3 was targeted on a high-affinity carbon nanotube by using computational tools. After analysis of 62 carbon nanotubes by multiple docking with the induced fit model, the top five compounds with high docking scores of − 7.94 kcal/mol, − 7.92 kcal/mol, − 7.28 kcal/mol, − 7.19 kcal/mol and − 7.09 kcal/mol (top hit1-5) were found to have inhibitory activity against the ORF8–IRF3 complex. Molecular dynamics analysis of the complexes revealed the high compactness of residues, stable binding, and strong hydrogen binding network among the ORF8-nanotubes complexes. Moreover, the total binding free energy for top hit1-5 was calculated to be − 43.21 ± 0.90 kcal/mol, − 41.17 ± 0.99 kcal/mol, − 48.85 ± 0.62 kcal/mol, − 43.49 ± 0.77 kcal/mol, and − 31.18 ± 0.78 kcal/mol respectively. These results strongly suggest that the identified top five nanotubes (hit1-5) possess significant potential for advancing and exploring innovative drug therapies. This underscores their suitability for subsequent in vivo and in vitro experiments, marking them as promising candidates worthy of further investigation.

Structural geometry, electronic properties and pre-clinical evaluation of antibacterial compounds from lichen-associated Streptomyces mobaraensis DRM1 and Nocardiopsis synnemataformans DRM2

Antibacterial compounds Phenol, 2,4-bis(1,1-dimethylethyl) and Lupeol obtained from lichen-associated Streptomyces mobaraensis DRM1 and Nocardiopsis synnemataformans DRM2 respectively. The geometry, electronic properties and binding affinities of antibacterial compound Phenol, 2,4-bis(1,1-dimethylethyl) and Lupeol was determined. The in silico molecular mechanics of bacterial growth inhibition by Phenol, 2,4-bis(1,1-dimethylethyl) and Lupeol was established in Pseudomonas aeroginosa and Salmonella typhi by molecular docking, molecular simulation approach. The bacterial growth is inhibited by inactivating the vital enzyme PqsA and actin in bacterial system of Pseudomonas and Salmonella. The antibacterial compound produced by lichen associated actinobiont are adhere to Lipinski rule 5 and established criteria for drug likeness with the acceptable ADME properties and expand our understanding of their pharmacological approach. Further it also revels the adaptation and survival lichen in adverse climatic condition through the antimicrobials in lichen-associated actinobiont.

Subtractive proteomics-guided vaccine targets identification and designing of multi-epitopes vaccine for immune response instigation against Burkholderia pseudomallei

In this study, a methodical workflow using subtractive proteomics, vaccine designing, molecular simulation, and agent-based modeling approaches were used to annotate the whole proteome of Burkholderia pseudomallei (strain K96243) for vaccine designing. Among the total 5717 proteins in the whole proteome, 505 were observed to be essential for the pathogen's survival and pathogenesis predicted by the Database of Essential Genes. Among these, 23 vaccine targets were identified, of which fimbrial assembly chaperone (Q63UH5), Outer membrane protein (Q63UH1), and Hemolysin-like protein (Q63UE4) were selected for the subsequent analysis based on the systematic approaches. Using immunoinformatic approaches CTL (cytotoxic T lymphocytes), HTL (helper T lymphocytes), IFN-positive, and B cell epitopes were predicted for these targets. A total of 9 CTL epitopes were added using the GSS linker, 6 HTL epitopes using the GPGPG linker, and 6 B cell epitopes using the KK linker. An adjuvant was added for enhanced antigenicity, an HIV-TAT peptide for improved delivery, and a PADRE sequence was added to form a 466 amino acids long vaccine construct. The construct was classified as non-allergenic, highly antigenic, and experimentally feasible. Molecular docking results validated the robust interaction of MEVC with immune receptors such as TLR2/4. Furthermore, molecular simulation revealed stable dynamics and compact nature of the complexes. The binding free energy results further validated the robust binding. In silico cloning, results revealed GC contents of 50.73 % and a CIA value of 0.978 which shows proper downstream processing. Immune simulation results reported that after the three injections of the vaccine a robust secondary immune response, improved antigen clearance, and effective immune memory generation were observed highlighting its potential for effective and sustained immunity. Future directions should encompass experimental validations, animal model studies, and clinical trials to substantiate the vaccine's efficacy, safety, and immunogenicity.

Investigating the role of functional mutations in leucine binding to Sestrin2 in aging and age-associated degenerative pathologies using structural and molecular simulation approaches

Leucine is the native known ligand of Sestrin2 (Sesn2) and its interaction with Sesn2 is particularly important, as it influences the activity of mTOR in aging and its associated pathologies. It is important to find out how leucine interacts with Sesn2 and how mutations in the binding pocket of leucine affect the binding of leucine. Therefore, this study was committed to investigating the impact of non-synonymous mutations by incorporating a broad spectrum of simulation techniques, from molecular dynamics to free energy calculations. Our study was designed to model the atomic-scale interactions between leucine and mutant forms of Sesn2. Our results demonstrated that the interaction paradigm for the mutants has been altered thus showing a significant decline in the hydrogen bonding network. Moreover, these mutations compromised the dynamic stability by altering the conformational flexibility, sampling time, and leucine-induced structural constraints that consequently caused variation in the binding and structural stability. Molecular dynamics-based flexibility analysis revealed that the regions 217–339 and 371–380 demonstrated a higher fluctuation. Noteworthy, these regions correspond to a linker (217–339) and a loop (371–380) that cover the leucine binding cavity that is critical for the ‘latch’ mechanism in the N-terminal, which is essential for leucine binding. Further validation of reduced binding and modified internal motions caused by the mutants was obtained through binding free energy calculations, principal components analysis (PCA), and free energy landscape (FEL) analysis. By unraveling the molecular intricacies of Sesn2-leucine interactions and their mutations, we hope to pave the way for innovative strategies to combat the inevitable tide of aging and its associated diseases. Communicated by Ramaswamy H. Sarma

Unraveling thermodynamic anomalies of water: A molecular simulation approach to probe the two-state theory with atomistic and coarse-grained water models.

Thermodynamic and dynamic anomalies of water play a crucial role in supporting life on our planet. The two-state theory attributes these anomalies to a dynamic equilibrium between locally favored tetrahedral structures (LFTSs) and disordered normal liquid structures. This theory provides a straightforward, phenomenological explanation for water's unique thermodynamic and dynamic characteristics. To validate this two-state feature, it is critical to unequivocally identify these structural motifs in a dynamically fluctuating disordered liquid. In this study, we employ a recently introduced structural parameter (θavg) that characterizes the local angular order within the first coordination shell to identify these LFTSs through molecular dynamics simulations. We employ both realistic water models with a liquid-liquid critical point (LLCP) and a coarse-grained water model without an LLCP to study water's anomalies in low-pressure regions below 2 kbar. The two-state theory consistently describes water's thermodynamic anomalies in these models, both with and without an LLCP. This suggests that the anomalies predominantly result from the two-state features rather than criticality, particularly within experimentally accessible temperature-pressure regions.

A Portrait of the Chromophore as a Young System-Quantum-Derived Force Field Unraveling Solvent Reorganization upon Optical Excitation of Cyclocurcumin Derivatives.

The study of fast non-equilibrium solvent relaxation in organic chromophores is still challenging for molecular modeling and simulation approaches, and is often overlooked, even in the case of non-adiabatic dynamics simulations. Yet, especially in the case of photoswitches, the interaction with the environment can strongly modulate the photophysical outcomes. To unravel such a delicate interplay, in the present contribution we resorted to a mixed quantum-classical approach, based on quantum mechanically derived force fields. The main task is to rationalize the solvent reorganization pathways in chromophores derived from cyclocurcumin, which are suitable for light-activated chemotherapy to destabilize cellular lipid membranes. The accurate and reliable decryption delivered by the quantum-derived force fields points to important differences in the solvent's reorganization, in terms of both structure and time scale evolution.

Exploring the potential of phytoconstituents from Phaseolus vulgaris L against C-X-C motif chemokine receptor 4 (CXCR4): a bioinformatic and molecular dynamic simulations approach

IntroductionThe CXCR4 chemokine receptor is a G protein-coupled receptor that plays a role in many physiological processes and diseases, such as cancer metastasis, HIV infection, and immune response. Because of this, it may be possible to target it therapeutically. In addition, the active ingredient of Phaseolus vulgaris L (PVL) has been reported to have anti-inflammatory, antioxidant, and anticancer properties. Novel CXCR4 antagonists from natural resources can be a promising drug development product using a computational approach. This study aims to explore the active compound in PVL that has the responsibility to inhibit CXCR4 using molecular docking and dynamics simulation.Materials and methodsPharmacokinetic analysis were performed using the pkCSM, OSIRIS for toxicity risk analysis, and the PerMM for membrane permeability assessment. Molecular docking was performed using PyRx software to determine the interaction between the CXCR4 target protein from the PDB database and the active component of PVL from the PubChem database. A molecular dynamics (MD) simulation was performed to determine the stability of the interaction using the WEBGRO Macromolecular Simulations online server. The analysis were performed by comparing the results with plerixafor as a control ligand.Results and discussionThe pharmacokinetic analysis of quercetin, kaempferol, myricetin, catechin, 3,4-dihydroxybenzoic acid, and daidzin in PVL showed that they met the drug-like criteria. These chemicals were expected to have medium-risk effects on mutagenesis and tumorigenesis, with the exception of catechin, which has no risk of toxicity, and daidzin, which has high-risk effects on mutagenesis and reproduction. Molecular docking identified that quercetin (− 6.6 kcal/mol), myricetin (− 6.6 kcal/mol), catechin (− 6.5 kcal/mol), and 3,4-dihydroxybenzoic acid (− 5.4 kcal/mol) bind to CXCR4 with the highest affinity compared to plerixafor (− 5.0 kcal/mol) and can bind to the same binding pocket with key residues Asp187, Asp97, and Glu288. The MD simulation analysis showed that quercetin has a similar stability interaction compared to the control.ConclusionsConsidering the pharmacokinetic analysis, molecular docking, and MD simulations, quercetin, myricetin, and 3,4-dihydroxybenzoic acid have the potential to become CXCR4 agonists with their good oral bioavailability and safety properties for the novel drug candidates. Future studies are needed to consider the molecular docking result.

Anti-Staphylococcus aureus potential of compounds from Ganoderma sp.: A comprehensive molecular docking and simulation approaches

In this study, a series of secondary metabolites from Ganoderma sp. were screened against Staphylococcus aureus protein targets, including as phosphotransacetylase, clumping factor A, and dihydrofolate reductase, using molecular docking simulations. The chemicals that showed the strongest binding energy with the targeted proteins were ganodermanontriol, lucidumol B, ganoderic acid J, ergosterol, ergosterol peroxide, 7-oxoganoderic acid Z, ganoderic acid AM1, ganosinoside A, ganoderic acid D, and 24R-ergosta-7,2E-diene-3β,5α,6β-triol. Interestingly, ganosinoside A showed the greatest affinity for the protein clumping factor A, a result validated by molecular dynamic simulation. Additionally, three natural Ganoderma sp. Strains as Ganoderma lingzhi VNKKK1903, Ganoderma lingzhi VNKK1905A2, and Amauroderma subresinosum VNKKK1904 were collected from Kon Ka Kinh National Park in central land of Vietnam and evaluated for their antibacterial activity against Staphylococcus aureus using an agar well diffusion technique. These results suggest that the fungal extracts and secondary metabolites may serve as valuable sources of antibiotics against Staphylococcus aureus. These findings provided an important scientific groundwork for further exploration of the antibacterial mechanisms of compounds derived from Ganoderma sp. in future research.

D-Glucosamine is a Potential Urease Inhibitor from Middle Eastern Medicinal Plants for Combatting Helicobacter Pylori Infections; a Molecular Docking and Simulation Approach.

Helicobacter pylori stands as a significant risk factor for both peptic and stomach ulcers. Their resistance to the highly acidic host environment primarily stems from their capability to produce urease, an enzyme that rapidly converts urea into NH3 and CO2. These byproducts are crucial for the bacterium's survival under such harsh conditions. Given the pivotal role of medicinal plants in treating various ailments with minimal side effects, there is an urgent need for a natural drug that can effectively eliminate H. pylori by inhibiting urease. Hence, the current study aims to identify the most potent urease inhibitor among the natural compounds found in Middle Eastern medicinal plants, taking into consideration factors such as optimal affinity, drug-like properties, pharmacokinetic characteristics, and thermodynamic attributes. In total, 5599 ligand conformers from 151 medicinal plants were subjected to docking against the urease's active site. The top-ranking natural compounds, as determined by their high docking scores, were selected for further analysis. Among these compounds, D-glucosamine (PubChem code 439,213) exhibited the most interactions with the crucial amino acid residues in the urease's active site. Furthermore, D-glucosamine demonstrated superior absorption, distribution, metabolism, excretion, and toxicity properties compared to other top-ranked candidates. Molecular dynamics simulations conducted over 100 nanoseconds revealed stable root mean square deviations and fluctuations of the protein upon complexation with D-glucosamine. Additionally, the radius of gyration and solvent-accessible surface area values for the D-glucosamine-urease complex were notably lower than those observed in other typical urease-inhibitor complexes. In conclusion, this study provides valuable insights into the potential development of D-glucosamine as a novel urease inhibitor. This promising compound holds the potential to serve as an effective drug for combating H. pylori infections in the near future.

Molecular insights into the interaction between myoglobin and Imidacloprid: Multi-spectral experiments and computational simulations

Imidacloprid (IMI) belongs to the neonicotinoid insecticides, specifically the imidazole chemical group, which exhibits a high level of contact, digestive, and systemic effects on the central nervous system of insects. In this study, we investigated the impact of IMI on the conformation and structural stability of myoglobin (Mb) protein using spectroscopic techniques combined with molecular docking and simulation approaches. Additionally, we examined the thermal stability of the resulting complex. The UV–Visible results demonstrated the interaction between IMI and Mb protein. The intrinsic fluorescence of Mb was effectively quenched by IMI, indicating successful binding and the formation of a stable complex. Thermodynamic analysis revealed that the spontaneous bonding process was primarily governed by van der Waals forces and hydrogen bonds. FT-IR analysis indicated that IMI induced conformational changes in Mb, providing further evidence of its potential toxicity and structural damage to Mb. Furthermore, the interaction significantly enhanced the thermal stability of Mb compared to Mb alone. Molecular docking revealed the preferred binding site of IMI within the Mb structure. Molecular dynamics (MD) simulation results further supported the findings by demonstrating a decrease in compactness and an increase in the stability of the Mb-IMI complex. These findings offer valuable insights into the potential toxicity risks of IMI to human health and shed light on the binding mechanism between IMI and Mb. The results of this study serve as a useful model for gaining a deeper understanding of the effects of these pesticides on proteins and body health.

Effect of mixed collector on the LRC flotation: an experimental and molecular dynamics simulation study

ABSTRACT To investigate the mechanism underlying the effect of mixed collector (MC) composed of diesel and span-80 on LRC flotation, a combination of experimental and molecular simulation approaches was employed. The flotation results demonstrated that the use of MC yielded superior flotation performance compared to diesel alone. The ratio of diesel to span-80 emerged as a key factor influencing the performance of MC collection. Furthermore, molecular dynamics (MD) simulations were employed to investigate the adsorption processes of dodecane and MC molecules on the LRC surface in the LRC/dodecane/water and LRC/MC/water systems, respectively. The analysis encompassed microstructure, dynamic properties, interaction energy, and hydrogen bonding. The findings indicated that the presence of span-80 molecules facilitated the direct entry of dodecane molecules in MC into “microscopic cavities,” thereby enhancing the adsorption of MC on the LRC surface. The analysis of interaction energy revealed a stronger interaction between MC molecules and the coal surface, with van der Waals energy playing a major role in the adsorption process. Additionally, span-80 molecules induced hydrogen bonding adsorption on the LRC surface.

Structural vaccinology, molecular simulation and immune simulation approaches to design multi-epitopes vaccine against John Cunningham virus

The JCV (John Cunningham Virus) is known to cause progressive multifocal leukoencephalopathy, a condition that results in the formation of tumors. Symptoms of this condition such as sensory defects, cognitive dysfunction, muscle weakness, homonosapobia, difficulties with coordination, and aphasia. To date, there is no specific and effective treatment to completely cure or prevent John Cunningham polyomavirus infections. Since the best way to control the disease is vaccination. In this study, the immunoinformatic tools were used to predict the high immunogenic and non-allergenic B cells, helper T cells (HTL), and cytotoxic T cells (CTL) epitopes from capsid, major capsid, and T antigen proteins of JC virus to design the highly efficient subunit vaccines. The specific immunogenic linkers were used to link together the predicted epitopes and subjected to 3D modeling by using the Robetta server. MD simulation was used to confirm that the newly constructed vaccines are stable and properly fold. Additionally, the molecular docking approach revealed that the vaccines have a strong binding affinity with human TLR-7. The codon adaptation index (CAI) and GC content values verified that the constructed vaccines would be highly expressed in E. coli pET28a (+) plasmid. The immune simulation analysis indicated that the human immune system would have a strong response to the vaccines, with a high titer of IgM and IgG antibodies being produced. In conclusion, this study will provide a pre-clinical concept to construct an effective, highly antigenic, non-allergenic, and thermostable vaccine to combat the infection of the John Cunningham virus.

Molecular simulation approaches to probing the effects of mechanical forces in the actin cytoskeleton.

Molecular simulation approaches to probing the effects of mechanical forces in the actin cytoskeleton.

Targeting the main SARS-Cov-2 pathways with peptide inhibitors by molecular docking and molecular simulation approaches

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to a significant global health crisis. The virus's spike glycoprotein (S protein) plays a pivotal role in facilitating viral entry and enhancing infectivity. In this study, we aimed to design peptides that can inhibit the interaction between the Omicron SARS-CoV-2 spike protein and its receptor ACE2, thereby preventing viral pathogenesis. We employed computational methods, including molecular docking and molecular dynamics simulations, to design and assess the binding affinity of peptide inhibitors. The crystal structure of the receptor-binding domain (RBD)-ACE2 complex was used as a template for peptide design. The designed peptides were evaluated for their stability, interaction strength, and binding affinity through molecular dynamics simulations. A library of peptide candidates was constructed, considering mutations that enhance binding affinity. The toxicity and allergenicity of the peptides were also assessed. Our results identified several promising peptide inhibitors with high affinity for the Omicron RBD domain. These peptides exhibited strong hydrophobic interactions and significant binding strengths. The findings suggest that these peptides could potentially inhibit viral fusion and pathogenicity, with P11 being the most potent inhibitor.

A multiscale molecular simulation approach for assessing the effects of mutation on protein activity and drug sensitivity of oncogenic kinases

A multiscale molecular simulation approach for assessing the effects of mutation on protein activity and drug sensitivity of oncogenic kinases

Repurposing FDA-approved drugs as NLRP3 inhibitors against inflammatory diseases: machine learning and molecular simulation approaches

Activation of NLRP3 (NOD-like receptor family, pyrin domain-containing protein 3) has been associated with multiple chronic pathologies, including diabetes, atherosclerosis, and rheumatoid arthritis. Moreover, histone deacetylases (HDACs), specifically HDAC6 is required for the NLRP3 inflammasome to assemble and activate. Thus, NLRP3 serves as an attractive target for the development of novel therapeutic approaches. Several companies are now attempting to develop specific modulators of the NLRP3 inflammasome, but only a handful of small molecules of NLRP3 inflammasome inhibitors, such as MCC950 and Tranilast, are currently available for clinical use. However, their use is limited due to severe side effects and short half-lives. Thus, the repurposing of FDA-approved drugs with NLRP3 inhibitory activity is needed. The present study was aimed at repurposing preexisting drugs that might act as safe and effective NLRP3 inhibitors. A library of 2,697 FDA-approved drugs was screened for binding with NLRP3 (PDB: 7ALV) using Glide (Schrödinger). The top seven FDA-approved drugs with potential binding affinities were selected based on docking scores and subjected to ADMET profiling using pkCSM and SwissADME. The binding of the ADMET-favorable FDA-approved drugs to NLRP3 was validated using MMGBSA (Prime) and Molecular Dynamics (Desmond) in the Schrödinger suite. ADMET profiling revealed that of the seven best docking drugs, empagliflozin and citicoline had good drug-likeness properties. Moreover, MMGBSA analysis and molecular dynamics demonstrated that empagliflozin and citicoline exhibited stable ligand-NLRP3 interactions in the presence of solvents. This study sheds light on the ability of various FDA-approved drugs to act as NLRP3 inhibitors. Communicated by Ramaswamy H. Sarma

Molecular simulation of [P8883][Tf2N] ionic liquid decorated silica in 6FDA-ODA based mixed matrix membrane for enhanced CO2/CH4 separation.

Mixed-matrix membranes (MMMs) have been reported to have considerable scope in gas separation applications because of their merged inherent strength of a durable polymer matrix and the exceptional performance capabilities of inorganic fillers. The selection of comparatively suitable polymers with fillers that can match each other and boost interfacial compatibility while ensuring uniform dispersion of filler within the polymer is still intensively demanding and is challenging at the experimental scale. Ionic liquids (ILs) are effective in promoting better dispersion and compatibility, leading to improved separation performance. A computational molecular simulation approach is employed in current work to design a hybrid membrane having Trioctapropyl phosphonium bis(trifluoromethylsulfonyl)imide [P8883][Tf2N] IL decorated silica as a filler and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride-4,4'-oxydianiline (6FDA-ODA) polymer for carbon dioxide (CO2) separation from methane (CH4). Thermophysical and gas transport properties under pure and mixed gas condition (30, 50, and 70% CO2/CH4) within the MMMs with varying filler loadings (5, 10, and 15 wt% IL-silica) are examined via Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) simulations. Membrane characteristics like glass transition temperature (T g), Fractional Free Volume (v f), X-Ray Diffraction (XRD), solubility, diffusivity, permeability, and selectivity for neat and IL-silica filled 6FDA-ODA are computed. The results show that the T g of the composite membrane with 5 wt% IL-silica is found to be considerably higher (with 305 °C) than that of the pure 6FDA-ODA polymer having 298 °C. A higher T g value highlights the effective dispersion and higher adhesion between the filler and polymer membrane. Additionally, CO2 permeability for 5 wt% IL-silica/6FDA-ODA MMM is significantly improved, measuring 319.0 barrer while maintaining a CO2/CH4 selectivity of 16.2. These values are 89% and 56% respectively, greater than the corresponding values of neat 6FDA-ODA membrane. Published data from the literature review is used to validate the findings and guarantee their reliability. The obtained results exhibited an error in the range of 0.7-9%. Hence, it is concluded from the study that molecular simulation can be used to design IL decorated silica incorporated within 6FDA-ODA matrix, which is able to boost the interfacial compatibility, with elevated CO2/CH4 selectivity and CO2 permeability.

HIV-1 Transcription Inhibition Using Small RNA-Binding Molecules.

The HIV-1 transactivator protein Tat interacts with the transactivation response element (TAR) at the three-nucleotide UCU bulge to facilitate the recruitment of transcription elongation factor-b (P-TEFb) and induce the transcription of the integrated proviral genome. Therefore, the Tat-TAR interaction, unique to the virus, is a promising target for developing antiviral therapeutics. Currently, there are no FDA-approved drugs against HIV-1 transcription, suggesting the need to develop novel inhibitors that specifically target HIV-1 transcription. We have identified potential candidates that effectively inhibit viral transcription in myeloid and T cells without apparent toxicity. Among these candidates, two molecules showed inhibition of viral protein expression. A molecular docking and simulation approach was used to determine the binding dynamics of these small molecules on TAR RNA in the presence of the P-TEFb complex, which was further validated by a biotinylated RNA pulldown assay. Furthermore, we examined the effect of these molecules on transcription factors, including the SWI/SNF complex (BAF or PBAF), which plays an important role in chromatin remodeling near the transcription start site and hence regulates virus transcription. The top candidates showed significant viral transcription inhibition in primary cells infected with HIV-1 (98.6). Collectively, our study identified potential transcription inhibitors that can potentially complement existing cART drugs to address the current therapeutic gap in current regimens. Additionally, shifting of the TAR RNA loop towards Cyclin T1 upon molecule binding during molecular simulation studies suggested that targeting the TAR loop and Tat-binding UCU bulge together should be an essential feature of TAR-binding molecules/inhibitors to achieve complete viral transcription inhibition.