Antiviral peptides against the main protease of SARS-CoV-2: A molecular docking and dynamics study

Hydrolyzing collagen by extracellular protease Hap of Aeromonas salmonicida: Turning chicken by-products into bioactive resources

Collagen-rich meat processing by-products have potential utilization value. Extracellular protease Hap from meat-borne Aeromonas salmonicida has been identified as an ideal protease for hydrolyzing collagen. Here, to explore the possible application of Hap for giving chicken by-products a high added value, the hydrolysis ability and mechanism were investigated. With a Vmax of 31.9 μg/mL/min and a Km of 1.18 mg/mL, Hap demonstrated obvious substrate specificity to pepsin-solubilized collagen (PSC) derived from chicken by-products, and significantly affected the tertiary structure and microstructure of PSC. Hap was found to preferentially cleave the peptide bond between Gly-X by peptide release kinetics, attacking from two ends to the middle region for α1 chain. Sixteen peptides are anticipated to be non-toxic with twenty potential biological activities at the end of hydrolysis. These observations will enrich the collagen hydrolysis mechanism of protease secreted by meat-borne bacteria and provide new insights into the utilization of meat by-products.

Discovery of sugar-based natural framework as phytopathogenic virus capsid protein inhibitors using a state-of-the-art multiple screening strategy

The prompt and efficient identification of targeted inhibitors against unscrupulous pathogenic viruses holds promise for preventing epidemic disease outbreaks. Herein, a comprehensive multichannel screening method (multiple docking cross-validation, molecular dynamics simulation, and density functional theory calculation) integrated with bioactivity identification is rationally established using sugar-based natural ligand libraries to target tobacco mosaic virus (TMV) capsid proteins. Encouragingly, compounds A0 (Kd = 0.14 μM) and A4 (Kd = 1.43 μM) were evaluated to have excellent binding capacities to TMV capsid protein, evidently exceeding that of viricide Ningnanmycin (Kd = 3.47 μM) by 24.8 and 2.4-folds. Moreover, A0 and A4 significantly down-regulated the expression of capsid proteins at the transcriptional level, effectively blocking the biosynthesis and assembly of TMV in tobacco. Additionally, bioactivity evaluation illustrated that the anti-TMV curative effects of A0 (EC50 = 310.9 μg/mL) and A4 (EC50 = 371.2 μg/mL) were comparable to Ningnanmycin (EC50 = 343.8 μg/mL). Considering the availability, cost and synthesis difficulty of precursors, the more affordable A4 is reckoned to be a promising candidate for capsid protein inhibitors and warrants further exploration in follow-up studies. Current findings highlight that this state-of-the-art virtual strategy, integrated with bioactivity validation, facilitates the discovery of targeted candidates to combat pathogenic viruses.

Multifaceted Analysis of Lactobacillus plantarum DMR14 Reveals Promising Antidiabetic Properties Through In Vivo Assays and Molecular Simulations

Due to the growing concern about diabetes worldwide, we investigated the antidiabetic potential of Lactobacillus plantarum DMR14, assessing its effects on the diabetic mice and identifying safe, bioactive compounds targeting DPP4 protein for drug development through various methods, including in vivo assays, GC-MS analysis and molecular docking simulations. The animal experiments showed that after 3 weeks of treatment, the blood sugar levels of mice given the bacteria were reduced by 35.03% compared to baseline. The treatment also significantly lowered blood lipids such as triglycerides, total cholesterol and LDL cholesterol, but did not affect HDL cholesterol levels. Additionally, we identified three compounds that effectively targeted a protein (DPP4) involved in diabetes (PDB ID: 4A5S). These compounds were predicted to be safe for absorption, processing and elimination by the body, and showed no signs of inducing cancer in computer simulations. Further simulations indicated that these compounds bind stably to the protein over time. Diabetic mice treated with Lactobacillus plantarum DMR14 exhibited improved organ health, reduced glucose levels and better metabolic markers. Computer analysis suggested compounds that could enhance enzyme inhibition, indicating potential antidiabetic properties in this strain. These suggested compounds could be considered potential candidates for developing antidiabetic drugs.

Selenicereus undatus (Dragon Fruit) Phytochemicals for Managing Three Human Pathogenic Bacteria: An In Vitro and In Silico Approach

OBJECTIVES

Antibiotic-resistant bacterial infections are a growing global concern. A natural remedy for bacterial infections could be available in the Selenicereus undatus fruit, but its antibacterial and biochemical properties are not fully known.

METHODS

In this study, the biochemical composition and antibacterial, antioxidant, and cytotoxic activities of the Jindu No. 1 (JD) and Bird's Nest (YW) dragon fruit varieties and their potential effects against E. coli, Pseudomonas sp., and Staphylococcus sp. were scrutinized.

RESULTS

The JD fruit extract showed higher antibacterial activity than the YW variety against E. coli, Pseudomonas sp., and Staphylococcus sp. in vitro. Additionally, the JD variety demonstrated more significant antioxidant activity than the YW variety and showed less cytotoxic activity. The JD variety had a higher glucose content, while the YW variety had a higher fructose content, and the phytoconstituents analysis confirmed 659 metabolites in total from the two varieties. Through in silico analyses, phytoconstituents were evaluated to identify potential drug molecules against the selected bacterial strain. Moreover, the molecular docking study revealed that riboprobe and Z-Gly-Pro might be effective against E. coli, 4-hydroxy retinoic acid, and that succinyl adenosine may target Pseudomonas sp., and xanthosine and 2'-deoxyinosine-5'-monophosphate may be effective against Staphylococcus sp. These results were further validated by 100 ns Molecular Dynamics (MD) simulation, and all of the selected compounds exhibited acceptable ADMET features.

CONCLUSIONS

Therefore, phytoconstituents from S. undatus fruit varieties could be employed to fight human bacterial diseases, and future studies will support the continuation of other biological activities in medical research.

In silico screening and evaluation of antiviral peptides as inhibitors against ORF9b protein of SARS-CoV-2

The present study investigated antiviral peptides (AVPs) as inhibitors of SARS-CoV-2 Orf9b protein, a novel target for disrupting the Orf9b-TOM70 complex crucial for viral infection. In silico screening via molecular docking and MD simulations identified AVP1442 and AVP1896 with high binding affinities to Orf9b (- 846.3 kcal mol-1 and - 820 kcal mol-1, respectively), comparable to the Orf9b-TOM70 complex (- 810.99 kcal mol-1). These AVPs interacted with key amino acid residues in Orf9b, including phosphorylation sites. In addition, AVPs also closely interacted with conserved regions in Orf9b. AVP1896 formed a hydrogen bond with Orf9b's threonine at position 84. AVP1442 interacted with Orf9b's leucine at position 15. Favorable Ramachandran plots and compactness during MD simulations for up to 100 ns suggest good stability of formed complexes. These non-toxic AVPs warrant further in vitro and in vivo evaluation, potentially as components of drug cocktails with small molecules or interferon-based therapies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04032-4.

HybAVPnet: A Novel Hybrid Network Architecture for Antiviral Peptides Prediction

Viruses pose a great threat to human production and life, thus the research and development of antiviral drugs is urgently needed. Antiviral peptides play an important role in drug design and development. Compared with the time-consuming and laborious wet chemical experiment methods, it is critical to use computational methods to predict antiviral peptides accurately and rapidly. However, due to limited data, accurate prediction of antiviral peptides is still challenging and extracting effective feature representations from sequences is crucial for creating accurate models. This study introduces a novel two-step approach, named HybAVPnet, to predict antiviral peptides with a hybrid network architecture based on neural networks and traditional machine learning methods. We adopted a stacking-like structure to capture both the long-term dependencies and local evolution information to achieve a comprehensive and diverse prediction using the predicted labels and probabilities. Using an ensemble technique with the different kinds of features can reduce the variance without increasing the bias. The experimental result shows HybAVPnet can achieve better and more robust performance compared with the state-of-the-art methods, which makes it useful for the research and development of antiviral drugs. Meanwhile, it can also be extended to other peptide recognition problems because of its generalization ability.

In-silico approach to characterize the structure and function of a hypothetical protein of Monkeypox virus exploring Chordopox-A20R domain-containing protein activity

Background: Monkeypox has emerged as a noteworthy worldwide issue due to its daily escalating case count. This illness presents diverse symptoms, including skin manifestations, which have the potential to spread through contact. The transmission of this infectious agent is intricate and readily transfers between individuals.Methods: The hypothetical protein MPXV-SI-2022V502225_00135 strain of monkeypox underwent structural and functional analysis using NCBI-CD Search, Pfam, and InterProScan. Quality assessment utilized PROCHECK, QMEAN, Verify3D, and ERRAT, followed by protein-ligand docking, visualization, and a 100-nanosecond simulation on Schrodinger Maestro.Results: Different physicochemical properties were estimated, indicating a stable molecular weight (49147.14) and theoretical pI (5.62) with functional annotation tools predicting the target protein to contain the domain of Chordopox_A20R domain. In secondary structure analysis, the helix coil was found to be predominant. The three-dimensional (3D) structure of the protein was obtained using a template protein (PDB ID: 6zyc.1), which became more stable after YASARA energy minimization and was validated by quality assessment tools like PROCHECK, QMEAN, Verify3D, and ERRAT. Protein-ligand docking was conducted using PyRx 9.0 software to examine the binding and interactions between a ligand and a hypothetical protein, focusing on various amino acids. The model structure, active site, and binding site were visualized using the CASTp server, FTsite, and PyMOL. A 100 nanosecond simulation was performed with ligand CID_16124688 to evaluate the efficiency of this protein.Conclusion: The analysis revealed significant binding interactions and enhanced stability, aiding in drug or vaccine design for effective antiviral treatment and patient management.

De novo design of potential peptide analogs against the main protease of Omicron variant using in silico studies

SARS-CoV-2 and its variants are crossing the immunity barrier induced through vaccination. Recent Omicron sub-variants are highly transmissible and have a low mortality rate. Despite the low severity of Omicron variants, these new variants are known to cause acute post-infectious syndromes. Nowadays, novel strategies to develop new potential inhibitors for SARS-CoV-2 and other Omicron variants have gained prominence. For viral replication and survival the main protease of SARS-CoV-2 plays a vital role. Peptide-like inhibitors that mimic the substrate peptide have already proved to be effective in inhibiting the Mpro of SARS-CoV-2 variants. Our systematic canonical amino acid point mutation analysis on the native peptide has revealed various ways to improve the native peptide of the main protease. Multi mutation analysis has led us to identify and design potent peptide-analog inhibitors that act against the Mpro of the Omicron sub-variants. Our in-depth analysis of all-atom molecular dynamics studies has paved the way to characterize the atomistic behavior of Mpro in Omicron variants. Our goal is to develop potent peptide-analogs that could be therapeutically effective against Omicron and its sub-variants.

Evaluating the Metabolomic Profile and Anti-Pathogenic Properties of Cannabis Species

The Cannabis species is one of the potent ancient medicinal plants acclaimed for its medicinal properties and recreational purposes. The plant parts are used and exploited all over the world for several agricultural and industrial applications. For many years Cannabis spp. has proven to present a highly diverse metabolomic profile with a pool of bioactive metabolites used for numerous pharmacological purposes ranging from anti-inflammatory to antimicrobial. Cannabis sativa has since been an extensive subject of investigation, monopolizing the research. Hence, there are fewer studies with a comprehensive understanding of the composition of bioactive metabolites grown in different environmental conditions, especially C. indica and a few other Cannabis strains. These pharmacological properties are mostly attributed to a few phytocannabinoids and some phytochemicals such as terpenoids or essential oils which have been tested for antimicrobial properties. Many other discovered compounds are yet to be tested for antimicrobial properties. These phytochemicals have a series of useful properties including anti-insecticidal, anti-acaricidal, anti-nematicidal, anti-bacterial, anti-fungal, and anti-viral properties. Research studies have reported excellent antibacterial activity against Gram-positive and Gram-negative multidrug-resistant bacteria as well as methicillin-resistant Staphylococcus aureus (MRSA). Although there has been an extensive investigation on the antimicrobial properties of Cannabis, the antimicrobial properties of Cannabis on phytopathogens and aquatic animal pathogens, mostly those affecting fish, remain under-researched. Therefore, the current review intends to investigate the existing body of research on metabolomic profile and anti-microbial properties whilst trying to expand the scope of the properties of the Cannabis plant to benefit the health of other animal species and plant crops, particularly in agriculture.

In vitro and in vivo evaluation of the antimicrobial, antioxidant, cytotoxic, hemolytic activities and in silico POM/DFT/DNA-binding and pharmacokinetic analyses of new sulfonamide bearing thiazolidin-4-ones

In this work, Schiff bases and Thiazolidin-4-ones, were synthesized using Sonication and Microwave techniques, respectively. The Schiff base derivatives (3a-b) were synthesized via the reaction of Sulfathiazole (1) with benzaldehyde derivatives (2a-b), followed by the synthesis of 4-thiazoledinone (4a-b) derivatives by cyclizing the synthesized Schiff bases through thioglycholic acid. All the synthesized compounds were characterized by spectroscopic techniques such as FT IR, NMR and HRMS. The synthesized compounds were tested for their in vitro antimicrobial and antioxidant and in vivo cytotoxicity and hemolysis ability. The synthesized compounds displayed better antimicrobial and antioxidant activity and low toxicity in comparison to reference drugs and negative controls, respectively. The hemolysis test revealed the compounds exhibit lower hemolytic effects and hemolytic values are comparatively low and the safety of compounds is in comparison with standard drugs. Theoretical calculations were carried out by using the molecular operating environment (MOE) and Gaussian computing software and observations were in good agreement with the in vitro and in vivo biological activities. Petra/Osiris/Molinspiration (POM) results indicate the presence of three combined antibacterial, antiviral and antitumor pharmacophore sites. The molecular docking revealed the significant binding affinities and non-bonding interactions between the compounds and Erwinia Chrysanthemi (PDB ID: 1SHK). The molecular dynamics simulation under in silico physiological conditions revealed a stable conformation and binding pattern in a stimulating environment. HighlightsNew series of Thaiazolidin-4-one derivatives have been synthesized.Sonication and microwave techniques are used.Antimicrobial, Antioxidant, cytotoxicity, and hemolysis activities were observed for all synthesized compounds.Molecular Docking and DFT/POM analyses have been predicted.Communicated by Ramaswamy H. Sarma.

Antiviral peptides inhibiting the main protease of SARS-CoV-2 investigated by computational screening and in vitro protease assay

The main protease (Mpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays an important role in viral replication and transcription and received great attention as a vital target for drug/peptide development. Therapeutic agents such as small-molecule drugs or peptides that interact with the Cys-His present in the catalytic site of Mpro are an efficient way to inhibit the protease. Although several emergency-approved vaccines showed good efficacy and drastically dropped the infection rate, evolving variants are still infecting and killing millions of people globally. While a small-molecule drug (Paxlovid) received emergency approval, small-molecule drugs have low target specificity and higher toxicity. Besides small-molecule drugs, peptide therapeutics are thus gaining increasing popularity as they are easy to synthesize and highly selective and have limited side effects. In this study, we investigated the therapeutic value of 67 peptides targeting Mpro using molecular docking. Subsequently, molecular dynamics (MD) simulations were implemented on eight protein-peptide complexes to obtain molecular-level information on the interaction between these peptides and the Mpro active site, which revealed that temporin L, indolicidin, and lymphocytic choriomeningitis virus (LCMV) GP1 are the best candidates in terms of stability, interaction, and structural compactness. These peptides were synthesized using the solid-phase peptide synthesis protocol, purified by reversed-phase high-performance liquid chromatography (RP-HPLC), and authenticated by mass spectrometry (MS). The in vitro fluorometric Mpro activity assay was used to validate the computational results, where temporin L and indolicidin were observed to be very active against SARS-CoV-2 Mpro with IC50 values of 38.80 and 87.23 μM, respectively. A liquid chromatography-MS (LC-MS) assay was developed, and the IC50 value of temporin L was measured at 23.8 μM. The solution-state nuclear magnetic resonance (NMR) structure of temporin L was determined in the absence of sodium dodecyl sulfate (SDS) micelles and was compared to previous temporin structures. This combined investigation provides critical insights and assists us to further develop peptide inhibitors of SARS-CoV-2 Mpro through structural guided investigation.

Exploring the Antarctic aminopeptidase P from Pseudomonas sp. strain AMS3 through structural analysis and molecular dynamics simulation

Aminopeptidase P (APPro) is a crucial metalloaminopeptidase involved in amino acid cleavage from peptide N-termini, playing essential roles as versatile biocatalysts with applications ranging from pharmaceuticals to industrial processes. Despite acknowledging its potential for catalysis in lower temperatures, detailed molecular basis and biotechnological implications in cold environments are yet to be explored. Therefore, this research aims to investigate the molecular mechanisms underlying the cold-adapted characteristics of APPro from Pseudomonas sp. strain AMS3 (AMS3-APPro) through a detailed analysis of its structure and dynamics. In this study, structure analysis and molecular dynamics (MD) simulation of a predicted model of AMS3-APPro has been performed at different temperatures to assess structural flexibility and thermostability across a temperature range of 0-60 °C over 100 ns. The MD simulation results revealed that the structure were able to remain stable at low temperatures. Increased temperatures present a potential threat to the overall stability of AMS3-APPro by disrupting the intricate hydrogen bond networks crucial for maintaining structural integrity, thereby increasing the likelihood of protein unfolding. While the metal binding site at the catalytic core exhibits resilience at higher temperatures, highlighting its local structural integrity, the overall enzyme structure undergoes fluctuations and potential denaturation. This extensive structural instability surpasses the localized stability observed at the metal binding site. Consequently, these assessments offer in-depth understanding of the cold-adapted characteristics of AMS3-APPro, highlighting its capability to uphold its native conformation and stability in low-temperature environments. In summary, this research provides valuable insights into the cold-adapted features of AMS3-APPro, suggesting its efficient operation in low thermal conditions, particularly relevant for potential biotechnological applications in cold environments.Communicated by Ramaswamy H. Sarma.

An in silico approach to develop potential therapies against Middle East Respiratory Syndrome Coronavirus (MERS-CoV)

A deadly respiratory disease Middle East Respiratory Syndrome (MERS) is caused by a perilous virus known as MERS-CoV, which has a severe impact on human health. Currently, there is no approved vaccine, prophylaxis, or antiviral therapeutics for preventing MERS-CoV infection. Due to its inexorable and integral role in the maturation and replication of the MERS-CoV virus, the 3C-like protease is unavoidly a viable therapeutic target. In this study, 2369 phytoconstituents were enlisted from Japanese medicinal plants, and these compounds were screened against 3C-like protease to identify feasible inhibitors. The best three compounds were identified as Kihadanin B, Robustaflavone, and 3-beta-O- (trans-p-Coumaroyl) maslinic acid, with binding energies of -9.8, -9.4, and -9.2 kcal/mol, respectively. The top three potential candidates interacted with several active site residues in the targeted protein, including Cys145, Met168, Glu169, Ala171, and Gln192. The best three compounds were assessed by in silico technique to determine their drug-likeness properties, and they exhibited the least harmful features and the greatest drug-like qualities. Various descriptors, such as solvent-accessible surface area, root-mean-square fluctuation, root-mean-square deviation, hydrogen bond, and radius of gyration, validated the stability and firmness of the protein-ligand complexes throughout the 100ns molecular dynamics simulation. Moreover, the top three compounds exhibited better binding energy along with better stability and firmness than the inhibitor (Nafamostat), which was further confirmed by the binding free energy calculation. Therefore, this computational investigation could aid in the development of efficient therapeutics for life-threatening MERS-CoV infections.

Recent advances in the exploration and discovery of SARS-CoV-2 inhibitory peptides from edible animal proteins

The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19), is spreading worldwide. Although the COVID-19 epidemic has passed its peak of transmission, the harm it has caused deserves our attention. Scientists are striving to develop medications that can effectively treat COVID-19 symptoms without causing any adverse reactions. SARS-CoV-2 inhibitory peptides derived from animal proteins have a wide range of functional activities in addition to safety. Identifying animal protein sources is crucial to obtaining SARS-CoV-2 inhibitory peptides from animal sources. This review aims to reveal the mechanisms of action of these peptides on SARS-CoV-2 and the possibility of animal proteins as a material source of SARS-CoV-2 inhibitory peptides. Also, it introduces the utilization of computer-aided design methods, phage display, and drug delivery strategies in the research on SARS-CoV-2 inhibitor peptides from animal proteins. In order to identify new antiviral peptides and boost their efficiency, we recommend investigating the interaction between SARS-CoV-2 inhibitory peptides from animal protein sources and non-structural proteins (Nsps) using a variety of technologies, including computer-aided drug approaches, phage display techniques, and drug delivery techniques. This article provides useful information for the development of novel anti-COVID-19 drugs.

In Silico Pharmacokinetics, Molecular Docking and Molecular Dynamics Simulation Studies of Nucleoside Analogs for Drug Discovery- A Mini Review

Nucleoside analogs have been widely used as antiviral, antitumor, and antiparasitic agents due to their ability to inhibit nucleic acid synthesis. Adenosine, cytidine, guanosine, thymidine and uridine analogs such as didanosine, vidarabine, remdesivir, gemcitabine, lamivudine, acyclovir, abacavir, zidovusine, stavudine, and idoxuridine showed remarkable anticancer and antiviral activities. In our previously published articles, our main intention was to develop newer generation nucleoside analogs with acylation-induced modification of the hydroxyl group and showcase their biological potencies. In the process of developing nucleoside analogs, in silico studies play an important role and provide a scientific background for biological data. Molecular interactions between drugs and receptors followed by assessment of their stability in physiological environments, help to optimize the drug development process and minimize the burden of unwanted synthesis. Computational approaches, such as DFT, FMO, MEP, ADMET prediction, PASS prediction, POM analysis, molecular docking, and molecular dynamics simulation, are the most popular tools to culminate all preclinical study data and deliver a molecule with maximum bioactivity and minimum toxicity. Although clinical drug trials are crucial for providing dosage recommendations, they can only indirectly provide mechanistic information through researchers for pathological, physiological, and pharmacological determinants. As a result, in silico approaches are increasingly used in drug discovery and development to provide mechanistic information of clinical value. This article portrays the current status of these methods and highlights some remarkable contributions to the development of nucleoside analogs with optimized bioactivity.

A computational simulation appraisal of banana lectin as a potential anti-SARS-CoV-2 candidate by targeting the receptor-binding domain

BACKGROUND

The ongoing concern surrounding coronavirus disease 2019 (COVID-19) primarily stems from continuous mutations in the genome of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leading to the emergence of numerous variants. The receptor-binding domain (RBD) in the S1 subunit of the S protein of the virus plays a crucial role in recognizing the host's angiotensin-converting enzyme 2 (hACE2) receptor and facilitating cell membrane fusion processes, making it a potential target for preventing viral entrance into cells. This research aimed to determine the potential of banana lectin (BanLec) proteins to inhibit SARS-CoV-2 attachment to host cells by interacting with RBD through computational modeling.

MATERIALS AND METHODS

The BanLecs were selected through a sequence analysis process. Subsequently, the genes encoding BanLec proteins were retrieved from the Banana Genome Hub database. The FGENESH online tool was then employed to predict protein sequences, while web-based tools were utilized to assess the physicochemical properties, allergenicity, and toxicity of BanLecs. The RBDs of SARS-CoV-2 were modeled using the SWISS-MODEL in the following step. Molecular docking procedures were conducted with the aid of ClusPro 2.0 and HDOCK web servers. The three-dimensional structures of the docked complexes were visualized using PyMOL. Finally, molecular dynamics simulations were performed to investigate and validate the interactions of the complexes exhibiting the highest interactions, facilitating the simulation of their dynamic properties.

RESULTS

The BanLec proteins were successfully modeled based on the RNA sequences from two species of banana (Musa sp.). Moreover, an amino acid modification in the BanLec protein was made to reduce its mitogenicity. Theoretical allergenicity and toxicity predictions were conducted on the BanLecs, which suggested they were likely non-allergenic and contained no discernible toxic domains. Molecular docking analysis demonstrated that both altered and wild-type BanLecs exhibited strong affinity with the RBD of different SARS-CoV-2 variants. Further analysis of the molecular docking results showed that the BanLec proteins interacted with the active site of RBD, particularly the key amino acids residues responsible for RBD's binding to hACE2. Molecular dynamics simulation indicated a stable interaction between the Omicron RBD and BanLec, maintaining a root-mean-square deviation (RMSD) of approximately 0.2 nm for a duration of up to 100 ns. The individual proteins also had stable structural conformations, and the complex demonstrated a favorable binding-free energy (BFE) value.

CONCLUSIONS

These results confirm that the BanLec protein is a promising candidate for developing a potential therapeutic agent for combating COVID-19. Furthermore, the results suggest the possibility of BanLec as a broad-spectrum antiviral agent and highlight the need for further studies to examine the protein's safety and effectiveness as a potent antiviral agent.

Molecular docking, simulations of animal peptides against the envelope protein of Dengue virus

Peptides are biologically active, small molecules with high specificity in its mode of action that can be effective at nanomolar concentrations. Peptide-based antiviral medicines have already been licensed and used to treat human immunodeficiency virus (HIV), influenza virus and hepatitis C virus. So far, no peptide drug has been approved for antiviral treatment against Dengue virus, and many are under clinical trials. Therefore, developing a reasonable peptide against the Dengue virus Envelope protein structure will be a successful strategy for treating Dengue. Hence, we investigated protein-protein docking interactions between 215 peptides retrieved from the AVP database against the envelope protein using Cluspro and HADDOCK followed by the evaluation of their allegenicity, toxicity and physicochemical characteristics investigation. Further validation of the protein-peptide complexes was performed with Molecular dynamics simulations and Molecular Mechanics Poisson-Boltzmann surface area (MMPBSA) analysis on the hit inhibitors. This study revealed that Indolicidin (-75.026 ± 1.54 KJ/mol) and Human Neutrophil peptide-1 (-71.6551 ± 2.112 KJ/mol) shows higher negative ΔG binding implicating their relative stabilization in the protein-peptide interactions during 100 ns of dynamic simulations. Also, both the peptides exhibited desirable physicochemical properties and were nonallergenic. Hence, we further aim to test these peptides by in vitro and in vivo studies to confirm their efficacy against Dengue virus.Communicated by Ramaswamy H. Sarma.

Effects of gamma-radiation on microbial, nutritional, and functional properties of Katimon mango peels: A combined biochemical and in silico studies

Gamma radiation has notable impacts on the flesh of mangoes. In this research, Katimon mangoes were subjected to different levels of irradiation (0.5, 1.0, 1.5, and 2.0 kGy) using a60Co irradiator. The results showed that irradiation significantly reduced the microbial population in the mango peels, with the 1.5 kGy dose showing the most significant reduction. Irradiation also delayed ripening and extended the shelf life of the mango peels. The total fat, protein, ash, moisture, and sugar content of the mango peels were all affected by irradiation. The total protein content, ash content and moisture content increased after irradiation, while the fat content remained relatively unchanged. The sugar content increased in all samples after storage, but the non-irradiated samples had higher sugar levels than the irradiated ones. The dietary fiber content of the mango peels was not significantly affected by irradiation. The vitamin C content decreased in all samples after storage. The titratable acidity and total soluble solids content of the mango peels increased after storage, but there were no significant differences between the irradiated and non-irradiated samples. Antioxidant activity and cytotoxicity assessment highlighted the antioxidant potential and reduced toxicity of irradiated samples. Additionally, the antimicrobial effectiveness of irradiated mango peels was evaluated. The most substantial inhibitory zones (measuring 16.90 ± 0.35) against Pseudomonas sp. were observed at a radiation dose of 1.5 kGy with 150 μg/disc. To identify potential antimicrobial agents, the volatile components of mangoes irradiated with 1.5 kGy were analyzed through GC-MS. Subsequently, these compounds were subjected to in silico studies against a viable protein, TgpA, of Pseudomonas sp. (PDB ID: 6G49). Based on molecular dynamic simulations and ADMET properties, (-)-Carvone (-6.2), p-Cymene (-6.1), and Acetic acid phenylmethyl ester (-6.1) were identified as promising compounds for controlling Pseudomonas sp.

Macromolecules: Synthesis, antimicrobial, POM analysis and computational approaches of some glucoside derivatives bearing acyl moieties

Macromolecules i.e., carbohydrate derivatives are crucial to biochemical and medical research. Herein, we designed and synthesized eight methyl α-D-glucopyranoside (MGP) derivatives (2-8) in good yields following the regioselective direct acylation method. The structural configurations of the synthesized MGP derivatives were analyzed and verified using multiple physicochemical and spectroscopic techniques. Antimicrobial experiments revealed that almost all derivatives demonstrated noticeable antifungal and antibacterial efficacy. The synthesized derivatives showed minimum inhibitory concentration (MIC) values ranging from 0.75 µg/mL to 1.50 µg/mL and minimum bactericidal concentrations (MBCs) ranging from 8.00 µg/mL to 16.00 µg/mL. Compound 6 inhibited Ehrlich ascites carcinoma (EAC) cell proliferation by 10.36% with an IC50 of 2602.23 μg/mL in the MTT colorimetric assay. The obtained results were further rationalized by docking analysis of the synthesized derivatives against 4URO and 4XE3 receptors to explore the binding affinities and nonbonding interactions of MGP derivatives with target proteins. Compound 6 demonstrated the potential to bind with the target with the highest binding energy. In a stimulating environment, a molecular dynamics study showed that MGP derivatives have a stable conformation and binding pattern. The MGP derivatives were examined using POM (Petra/Osiris/Molinspiration) bioinformatics, and as a result, these derivatives showed good toxicity, bioavailability, and pharmacokinetics. Various antifungal/antiviral pharmacophore (Oδ-, O'δ-) sites were identified by using POM investigations, and compound 6 was further tested against other pathogenic fungi and viruses, such as Micron and Delta mutants of SARS-CoV-2.

Computational prediction of B and T-cell epitopes of Kyasanur Forest Disease virus marker proteins towards the development of precise diagnosis and potent subunit vaccine

Kyasanur Forest Disease (KFD), also known as 'monkey fever', caused by KFD Virus (KFDV), is a highly neglected tropical disease endemic to Western Ghat region of Karnataka, India. Recently, KFD, which is fatal for both monkeys and humans with a mortality rate of 2-10% has been found to spread from its epicenter to neighboring districts and states also. The current ELISA based KFD detection method is very non-specific due to cross-reactivity with other flaviviruses. Further, presently available formalin-inactivated vaccine has been found to be less effective leading to disease susceptibility and severity. To address these, the present study was aimed at predicting the potent specific B and T-cell epitopes of KFDV immunogenic marker proteins using diverse computational tools aiming at developing precise diagnostic method and an effective subunit vaccine. Here, we have chosen E, NS1 and NS5 proteins as markers of KFDV by taking into account of their differential and non-overlapping sequences with selected arboviruses. Based on the linear and nonlinear epitope prediction tools and important biophysical parameters, we identified three potential linear and ten nonlinear B-cell epitopes. We also predicted T-cell epitope peptides which binds to MHC class-I and class-II receptors for the effective T-cell activation. Thus, our molecular docking and molecular dynamics simulation analysis has identified six different TH-cell epitopes based on the distribution frequency of MHC-II haplotypes in the human population and one TC-cell epitope from NS5 protein that has maximum interaction with class-I MHC. Overall, we have successfully identified potential B and T-cell epitope marker peptides present in the envelope and two non-structural proteins.Communicated by Ramaswamy H. Sarma.

Prospecting native and analogous peptides with anti-SARS-CoV-2 potential derived from the trypsin inhibitor purified from tamarind seeds

The study aimed to prospect in silico native and analogous peptides with anti-SARS-CoV-2 potential derived from the trypsin inhibitor purified from tamarind seeds (TTIp). From the most stable theoretical model of TTIp (TTIp 56/287), in silico cleavage was performed for the theoretical identification of native peptides and generation of analogous peptides. The anti-SARS-CoV-2 potential was investigated through molecular dynamics (MD) simulation between the peptides and binding sites of transmembrane serine protease 2 (TMPRSS2), responsible for the entry of SARS-CoV-2 into the host cell. Five native and analogous peptides were obtained and validated through chemical and physical parameters. The best interaction potential energy (IPE) occurred between TMPRSS2 and one of the native peptides obtained by cleavage with trypsin and its analogous peptide. Thus, both peptides showed many hydrophobic residues, a common physical-chemical property among the peptides that inhibit the entry of enveloped viruses, such as SARS-CoV-2, present in specific drugs to treat COVID-19.

A Computational Study on Selected Alkaloids as SARS-CoV-2 Inhibitors: PASS Prediction, Molecular Docking, ADMET Analysis, DFT, and Molecular Dynamics Simulations

Despite treatments and vaccinations, it remains difficult to develop naturally occurring COVID-19 inhibitors. Here, our main objective is to find potential lead compounds from the retrieved alkaloids with antiviral and other biological properties that selectively target the main SARS-CoV-2 protease (Mpro), which is required for viral replication. In this work, 252 alkaloids were aligned using Lipinski's rule of five and their antiviral activity was then assessed. The prediction of activity spectrum of substances (PASS) data was used to confirm the antiviral activities of 112 alkaloids. Finally, 50 alkaloids were docked with Mpro. Furthermore, assessments of molecular electrostatic potential surface (MEPS), density functional theory (DFT), and absorption, distribution, metabolism, excretion, and toxicity (ADMET) were performed, and a few of them appeared to have potential as candidates for oral administration. Molecular dynamics simulations (MDS) with a time step of up to 100 ns were used to confirm that the three docked complexes were more stable. It was found that the most prevalent and active binding sites that limit Mpro'sactivity are PHE294, ARG298, and GLN110. All retrieved data were compared to conventional antivirals, fumarostelline, strychnidin-10-one (L-1), 2,3-dimethoxy-brucin (L-7), and alkaloid ND-305B (L-16) and were proposed as enhanced SARS-CoV-2 inhibitors. Finally, with additional clinical or necessary study, it may be able to use these indicated natural alkaloids or their analogs as potential therapeutic candidates.

Amentoflavone derivatives significantly act towards the main protease (3CLPRO/MPRO) of SARS-CoV-2: in silico admet profiling, molecular docking, molecular dynamics simulation, network pharmacology

SARS-CoV-2 is the foremost culprit of the novel coronavirus disease 2019 (nCoV-19 and/or simply COVID-19) and poses a threat to the continued life of humans on the planet and create pandemic issue globally. The 3-chymotrypsin-like protease (MPRO or 3CLPRO) is the crucial protease enzyme of SARS-CoV-2, which directly involves the processing and release of translated non-structural proteins (nsps), and therefore involves the development of virus pathogenesis along with outbreak the forecasting of COVID-19 symptoms. Moreover, SARS-CoV-2 infections can be inhibited by plant-derived chemicals like amentoflavone derivatives, which could be used to develop an anti-COVID-19 drug. Our research study is designed to conduct an in silico analysis on derivatives of amentoflavone (isoginkgetin, putraflavone, 4''''''-methylamentoflavone, bilobetin, ginkgetin, sotetsuflavone, sequoiaflavone, heveaflavone, kayaflavone, and sciadopitysin) for targeting the non-structural protein of SARS-CoV-2, and subsequently further validate to confirm their antiviral ability. To conduct all the in silico experiments with the derivatives of amentoflavone against the MPRO protein, both computerized tools and online servers were applied; notably the software used is UCSF Chimera (version 1.14), PyRx, PyMoL, BIOVIA Discovery Studio tool (version 4.5), YASARA (dynamics simulator), and Cytoscape. Besides, as part of the online tools, the SwissDME and pKCSM were employed. The research study was proposed to implement molecular docking investigations utilizing compounds that were found to be effective against the viral primary protease (MPRO). MPRO protein interacted strongly with 10 amentoflavone derivatives. Every time, amentoflavone compounds outperformed the FDA-approved antiviral medicine that is currently underused in COVID-19 in terms of binding affinity (- 8.9, - 9.4, - 9.7, - 9.1, - 9.3, - 9.0, - 9.7, - 9.3, - 8.8, and - 9.0 kcal/mol, respectively). The best-selected derivatives of amentoflavone also possessed potential results in 100 ns molecular dynamic simulation (MDS) validation. It is conceivable that based on our in silico research these selected amentoflavone derivatives more precisely 4''''''-methylamentoflavone, ginkgetin, and sequoiaflavone have potential for serving as promising lead drugs against SARS-CoV-2 infection. In consequence, it is recommended that additional in vitro as well as in vivo research studies have to be conducted to support the conclusions of this current research study.

Drug Repurposing and Systems Biology approaches of Enzastaurin can target potential biomarkers and critical pathways in Colorectal Cancer

Colorectal cancer (CRC) is a severe health concern that results from a cocktail of genetic, epigenetic, and environmental abnormalities. Because it is the second most lethal malignancy in the world and the third-most common malignant tumor, but the treatment is unavailable. The goal of the current study was to use bioinformatics and systems biology techniques to determine the pharmacological mechanism underlying putative important genes and linked pathways in early-onset CRC. Computer-aided methods were used to uncover similar biological targets and signaling pathways associated with CRC, along with bioinformatics and network pharmacology techniques to assess the effects of enzastaurin on CRC. The KEGG and gene ontology (GO) pathway analysis revealed several significant pathways including in positive regulation of protein phosphorylation, negative regulation of the apoptotic process, nucleus, nucleoplasm, protein tyrosine kinase activity, PI3K-Akt signaling pathway, pathways in cancer, focal adhesion, HIF-1 signaling pathway, and Rap1 signaling pathway. Later, the hub protein module identified from the protein-protein interactions (PPIs) network, molecular docking and molecular dynamics simulation represented that enzastaurin showed strong binding interaction with two hub proteins including CASP3 (-8.6 kcal/mol), and MCL1 (-8.6 kcal/mol), which were strongly implicated in CRC management than other the five hub proteins. Moreover, the pharmacokinetic features of enzastaurin revealed that it is an effective therapeutic agent with minimal adverse effects. Enzastaurin may inhibit the potential biological targets that are thought to be responsible for the advancement of CRC and this study suggests a potential novel therapeutic target for CRC.

Can Probiotics, Particularly Limosilactobacillus fermentum UCO-979C and Lacticaseibacillus rhamnosus UCO-25A, Be Preventive Alternatives against SARS-CoV-2?

COVID-19, an infection produced by the SARS-CoV-2 virus in humans, has rapidly spread to become a high-mortality pandemic. SARS-CoV-2 is a single-stranded RNA virus characterized by infecting epithelial cells of the intestine and lungs, binding to the ACE2 receptor present on epithelial cells. COVID-19 treatment is based on antivirals and antibiotics against symptomatology in addition to a successful preventive strategy based on vaccination. At this point, several variants of the virus have emerged, altering the effectiveness of treatments and thereby attracting attention to several alternative therapies, including immunobiotics, to cope with the problem. This review, based on articles, patents, and an in silico analysis, aims to address our present knowledge of the COVID-19 disease, its symptomatology, and the possible beneficial effects for patients if probiotics with the characteristics of immunobiotics are used to confront this disease. Moreover, two probiotic strains, L. fermentum UCO-979C and L. rhamnosus UCO-25A, with different effects demonstrated at our laboratory, are emphasized. The point of view of this review highlights the possible benefits of probiotics, particularly those associated with immunomodulation as well as the production of secondary metabolites, and their potential targets during SARS-CoV-2 infection.

Integrated Computational Approaches for Inhibiting Sex Hormone-Binding Globulin in Male Infertility by Screening Potent Phytochemicals

Male infertility is significantly influenced by the plasma-protein sex hormone-binding globulin (SHBG). Male infertility, erectile dysfunction, prostate cancer, and several other male reproductive system diseases are all caused by reduced testosterone bioavailability due to its binding to SHBG. In this study, we have identified 345 phytochemicals from 200 literature reviews that potentially inhibit severe acute respiratory syndrome coronavirus 2. Only a few studies have been done using the SARS-CoV-2 inhibitors to identify the SHBG inhibitor, which is thought to be the main protein responsible for male infertility. In virtual-screening and molecular-docking experiments, cryptomisrine, dorsilurin E, and isoiguesterin were identified as potential SHBG inhibitors with binding affinities of -9.2, -9.0, and -8.8 kcal/mol, respectively. They were also found to have higher binding affinities than the control drug anastrozole (-7.0 kcal/mol). In addition to favorable pharmacological properties, these top three phytochemicals showed no adverse effects in pharmacokinetic evaluations. Several molecular dynamics simulation profiles' root-mean-square deviation, radius of gyration, root-mean-square fluctuation, hydrogen bonds, and solvent-accessible surface area supported the top three protein-ligand complexes' better firmness and stability than the control drug throughout the 100 ns simulation period. These combinatorial drug-design approaches indicate that these three phytochemicals could be developed as potential drugs to treat male infertility.

Klebsiella pneumoniae Volatile Organic Compounds (VOCs) Protect Artemia salina from Fish Pathogen Aeromonas sp.: A Combined In Vitro, In Vivo, and In Silico Approach

Antibiotic resistance is an alarming threat all over the world, and the biofilm formation efficacy of bacteria is making the situation worse. The antagonistic efficacy of Klebsiella pneumoniae against one of the known fish pathogens, Aeromonas sp., is examined in this study. Moreover, Aeromonas sp.'s biofilm formation ability and in vivo pathogenicity on Artemia salina are also justified here. Firstly, six selected bacterial strains were used to obtain antimicrobial compounds against this pathogenic strain. Among those, Klebsiella pneumoniae, another pathogenic bacterium, surprisingly demonstrated remarkable antagonistic activity against Aeromonas sp. in both in vitro and in vivo assays. The biofilm distrusting potentiality of Klebsiella pneumoniae's cell-free supernatants (CFSs) was likewise found to be around 56%. Furthermore, the volatile compounds of Klebsiella pneumoniae were identified by GC-MS in order to explore compounds with antibacterial efficacy against Aeromonas sp. through an in silico study, where 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) (PDB: 5B7P) was chosen as a target protein for its unique characteristics and pathogenicity. Several volatile compounds, such as oxime- methoxy-phenyl-, fluoren-9-ol, 3,6-dimethoxy-9-(2-phenylethynyl)-, and 2H-indol-2-one, 1,3-dihydro- showed a strong binding affinity, with free energy of -6.7, -7.1, and -6.4 Kcal/mol, respectively, in complexes with the protein MTAN. Moreover, the root-mean-square deviation, solvent-accessible surface area, radius of gyration, root-mean-square fluctuations, and hydrogen bonds were used to ensure the binding stability of the docked complexes in the atomistic simulation. Thus, Klebsiella pneumoniae and its potential compounds can be employed as an alternative to antibiotics for aquaculture, demonstrating their effectiveness in suppressing Aeromonas sp.

Potential inhibitory properties of structurally modified quercetin/isohamnetin glucosides against SARS-CoV-2 Mpro; molecular docking and dynamics simulation strategies

Concerned organizations and individuals are fully engaged in seeking appropriate measures towards managing Severe Acute Respiratory Syndrome Coronavirus 2 (SAR-CoV-2) infection because of the unprecedented economic and health impact. SAR-CoV-2 Main protease (SARS-CoV-2 Mpro) is unique to the survival and viability of the virus. Therefore, inhibition of Mpro can block the viral propagation. Thirty (30) derivatives were built by changing the glucosides in the Meta and para position of quercetin and isohamnetin. Molecular docking analysis was used for the screening of the compounds. Dynamics simulation was performed to assess the stability of the best pose docked complex. Molecular mechanics binding free energy calculation was done by Molecular Mechanics/Poisson-Boltzmann Surface Area (MMPBSA). Overall analysis showed that the compounds are allosteric inhibitors of SARS-CoV-2 Mpro. Dynamic simulation analysis established the stability of Mpro-ISM-1, Mpro-ISD-3, Mpro-IST-2, Mpro-QM-2, and Mpro-QD-6 complexes with a maximum of 7 hydrogen bonds involved in their interaction. The MMPBSA binding free energies for ISM-1, ISD-3, IST-2, QM-2, and QD-6 were -92.47 ± 9.06, -222.27 ± 32.5, 180.72 ± 47.92, 156.46 ± 49.88 and -93.52 ± 48.75 kcal/mol respectively. All the compounds showed good pharmacokinetic properties, while only ISM-1 inhibits hERG and might be cardio-toxic. Observations in this study established that the glucoside position indeed influenced the affinity for SARS-CoV-2 Mpro. The study also suggested the potentials of ISD-3, QM-2 and QD-6 as potent inhibitors of the main protease, further experimental and clinical studies are however necessary to validate and establish the need for further drug development processes. Therefore, future studies will be on the chemical synthesis of the compounds and investigation of the in-vitro inhibition of SARS-CoV-2.

Cell-Free Supernatants (CFSs) from the Culture of Bacillus subtilis Inhibit Pseudomonas sp. Biofilm Formation

Biofilm inhibition has been identified as a novel drug target for the development of broad-spectrum antibiotics to combat infections caused by drug-resistant bacteria. Although several plant-based compounds have been reported to have anti-biofilm properties, research on the anti-biofilm properties of bacterial bioactive compounds has been sparse. In this study, the efficacy of compounds from a cell-free supernatant of Bacillus subtilis against a biofilm formation of Pseudomonas sp. was studied through in vitro, in vivo and in silico studies. Here, in well diffusion method, Bacillus subtilis demonstrated antibacterial activity, and more than 50% biofilm inhibition activity against Pseudomonas sp. was exhibited through in vitro studies. Moreover, molecular docking and molecular dynamics (MD) simulation gave insights into the possible mode of action of the bacterial volatile compounds identified through GC-MS to inhibit the biofilm-formation protein (PDB ID: 7M1M) of Pseudomonas sp. The binding energy revealed from docking studies ranged from -2.3 to -7.0 kcal mol-1. Moreover, 1-(9H-Fluoren-2-yl)-2-(1-phenyl-1H-ttetrazole5-ylsulfanyl)-ethanone was found to be the best-docked compound through ADMET and pharmacokinetic properties. Furthermore, MD simulations further supported the in vitro studies and formed a stable complex with the tested protein. Thus, this study gives an insight into the development of new antibiotics to combat multi-drug-resistant bacteria.

Biological Efficacy of Compounds from Stingless Honey and Sting Honey against Two Pathogenic Bacteria: An In Vitro and In Silico Study

Honey inhibits bacterial growth due to the high sugar concentration, hydrogen peroxide generation, and proteinaceous compounds present in it. In this study, the antibacterial activity of stingless and sting honey against foodborne pathogenic bacteria isolated from spoiled milk samples was examined. The isolated bacterial strains were confirmed as Bacillus cereus and Listeriamonocytogenes through morphological, biochemical, and 16 s RNA analysis. Physiochemical characterizations of the honey samples revealed that both of the honey samples had an acidic pH, low water content, moderate reducing sugar content, and higher proline content. Through the disc diffusion method, the antibacterial activities of the samples were assayed and better results were observed for the 50 mg/disc honey. Both stingless and sting honey showed the most positive efficacy against Bacillus cereus. Therefore, an in silico study was conducted against this bacterium with some common compounds of honey. From several retrieved constituents of stingless and sting honey, 2,4-dihydroxy-2,5-dimethyl 3(2H)-furan-3-one (furan) and 4H-pyran-4-one,2,3-dihydro of both samples and beta.-D-glucopyranose from the stingless revealed high ligand-protein binding efficiencies for the target protein (6d5z, hemolysin II). The root-mean-square deviation, solvent-accessible surface area, the radius of gyration, root-mean-square fluctuations, and hydrogen bonds were used to ensure the binding stability of the docked complexes in the atomistic simulation and confirmed their stability. The combined effort of wet and dry lab-based work support, to some extent, that the antimicrobial properties of honey have great potential for application in medicine as well as in the food industries.

Revealing the Acetylcholinesterase Inhibitory Potential of Phyllanthus amarus and Its Phytoconstituents: In Vitro and in Silico Approach

The inhibition of acetylcholinesterase plays a vital role in the treatment of Alzheimer disease. This study aimed to explore the acetylcholinesterase inhibition potential of Phyllanthus amarus and its phytoconstituents through an in vitro and in silico approach. The in vitro acetylcholinesterase inhibitory activity of P amarus was carried out, followed by the molecular docking studies of its phytoconstituents. The top-ranked molecules identified through molecular docking were subjected to molecular dynamics simulation (MDS) and density functional theory (DFT) studies. The results obtained revealed the methanolic extract of P amarus as a potent acetylcholinesterase inhibitor, while amarosterol A, hinokinin, β-sitosterol, stigmasterol and ellagic acid were identified as potential acetylcholinesterase inhibitors. The MDS and DFT results are in agreement with those obtained from the docking studies. Our findings suggest further studies on the hit molecules.

Missense mutations in spike protein of SARS-CoV-2 delta variant contribute to the alteration in viral structure and interaction with hACE2 receptor

INTRODUCTION

Many of the global pandemics threaten human existence over the decades among which coronavirus disease (COVID-19) is the newest exposure circulating worldwide. The RNA encoded severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is referred as the pivotal agent of this deadly disease that induces respiratory tract infection by interacting host ACE2 receptor with its spike glycoprotein. Rapidly evolving nature of this virus modified into new variants helps in perpetrating immune escape and protection against host defense mechanism. Consequently, a new isolate, delta variant originated from India is spreading perilously at a higher infection rate.

METHODS

In this study, we focused to understand the conformational and functional significance of the missense mutations found in the spike glycoprotein of SARS-CoV-2 delta variant performing different computational analysis.

RESULTS

From physiochemical analysis, we found that the acidic isoelectric point of the virus elevated to basic pH level due to the mutations. The targeted mutations were also found to change the interactive bonding pattern and conformational stability analyzed by the molecular dynamic's simulation. The molecular docking study also revealed that L452R and T478K mutations found in the RBD domain of delta variant spike protein contributed to alter interaction with the host ACE2 receptor.

CONCLUSIONS

Overall, this study provided insightful evidence to understand the morphological and attributive impact of the mutations on SARS-CoV-2 delta variant.

Repurposing small molecules of Tephrosia purpurea against SARS-CoV-2 main protease

Coronavirus infection is a communicable disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which emerged as a global pandemic with deteriorating effect on the world's population. Main protease (M^pro) of SARS-CoV-2 plays a significant role in the viral replication, transcription and disease propagation as well as a potential candidate for drug discovery and development for COVID-19 infection. The current study employed state of art structure-based drug discovery to decipher the role of phytochemicals of Tephrosia purpurea against M^pro. Tephrosia purpurea is being used as a traditional medicinal plant for the treatment of cough, breathlessness and fever as per the Indian Materia Medica. Screening of the phytochemicals of Tephrosia purpurea against M^pro was performed using molecular docking approach to identify the top 5 hits (+)-tephrorin B, deguelin, vitamin p, lanceolarin and 3beta-hydroxy-20(29)-lupene with binding energy of -8.4, -8.1, -8.0, -7.8, and -7.8 kcal/mol, respectively. Furthermore, identified top 5 hits were subjected to drug-likeness and toxicity prediction as well as MM-GBSA calculation. Out of the five molecules four molecules were predicted not to comprise any mutagenic and carcinogenic effects. Top two molecules based on the drug-likeness properties for oral bio-availability were further analysed by molecular dynamics simulation at 100 ns timescale. It was observed from the dynamic behaviour of the two complexes that the addition of these molecules changed the conformation and stability of the apo protein; thus may act as inhibitors for M^pro.Communicated by Ramaswamy H. Sarma.

Bioactive Antimicrobial Peptides: A New Weapon to Counteract Zoonosis

Zoonoses have recently become the center of attention of the general population and scientific community. Notably, more than 30 new human pathogens have been identified in the last 30 years, 75% of which can be classified as zoonosis. The complete eradication of such types of infections is far out of reach, considering the limited understanding of animal determinants in zoonoses and their causes of emergence. Therefore, efforts must be doubled in examining the spread, persistence, and pathogenicity of zoonosis and studying possible clinical interventions and antimicrobial drug development. The search for antimicrobial bioactive compounds has assumed great emphasis, considering the emergence of multi-drug-resistant microorganisms. Among the biomolecules of emerging scientific interest are antimicrobial peptides (AMPs), potent biomolecules that can potentially act as important weapons against infectious diseases. Moreover, synthetic AMPs are easily tailored (bioinformatically) to target specific features of the pathogens to hijack, inducing no or very low resistance. Although very promising, previous studies on SAMPs' efficacy are still at their early stages. Indeed, further studies and better characterization on their mechanism of action with in vitro and in vivo assays are needed so as to proceed to their clinical application on human beings.

Modern drug discovery applications for the identification of novel candidates for COVID-19 infections

In early December 2019, a large pneumonia epidemic occurred in Wuhan, China. The World Health Organization is concerned about the outbreak of another coronavirus with the powerful, rapid, and contagious transmission. Anyone with minor symptoms like fever and cough or travel history to contaminated places might be suspected of having COVID-19. COVID-19 therapy focuses on treating the disease's symptoms. So far, no such therapeutic molecule has been shown effective in treating this condition. So the treatment is mostly supportive and plasma. Globally, numerous studies and researchers have recently started fighting this virus. Vaccines and chemical compounds are also being investigated against infection. COVID-19 was successfully diagnosed using RNA detection and very sensitive RT-PCR (reverse transcription-polymerase chain reaction). The evolution of particular vaccinations is required to reduce illness severity and spread. Numerous computational analyses and molecular docking have predicted various target compounds that might stop this condition. This paper examines the main characteristics of coronavirus and the computational analyses necessary to avoid infection.

Synthesis, antimicrobial, molecular docking and molecular dynamics studies of lauroyl thymidine analogs against SARS-CoV-2: POM study and identification of the pharmacophore sites

Nucleoside precursors and nucleoside analogs occupy an important place in the treatment of viral respiratory pathologies, especially during the current COVID-19 pandemic. From this perspective, the present study has been designed to explore and evaluate the synthesis and spectral characterisation of 5́-O-(lauroyl) thymidine analogs 2-6 with different aliphatic and aromatic groups through comprehensive in vitro antimicrobial screening, cytotoxicity assessment, physicochemical aspects, molecular docking and molecular dynamics analysis, along with pharmacokinetic prediction. A unimolar one-step lauroylation of thymidine under controlled conditions furnished the 5́-O-(lauroyl) thymidine and indicated the selectivity at C-5́ position and the development of thymidine based potential antimicrobial analogs, which were further converted into four newer 3́-O-(acyl)-5́-O-(lauroyl) thymidine analogs in reasonably good yields. The chemical structures of the newly synthesised analogs were ascertained by analysing their physicochemical, elemental, and spectroscopic data. In vitro antimicrobial tests against five bacteria and two fungi, along with the prediction of activity spectra for substances (PASS), indicated promising antibacterial functionality for these thymidine analogs compared to antifungal activity. In support of this observation, molecular docking experiments have been performed against the main protease of SARS-CoV-2, and significant binding affinities and non-bonding interactions were observed against the main protease (6LU7, 6Y84 and 7BQY), considering hydroxychloroquine (HCQ) as standard. Moreover, the 100 ns molecular dynamics simulation process was performed to monitor the behaviour of the complex structure formed by the main protease under in silico physiological conditions to examine its stability over time, and this revealed a stable conformation and binding pattern in a stimulating environment of thymidine analogs. Cytotoxicity determination confirmed that compounds were found less toxic. Pharmacokinetic predictions were investigated to evaluate their absorption, distribution, metabolism and toxic properties, and the combination of pharmacokinetic and drug-likeness predictions has shown promising results in silico. The POM analysis shows the presence of an antiviral (O1δ-, O2δ-) pharmacophore site. Overall, the current study should be of great help in the development of thymidine-based, novel, multiple drug-resistant antimicrobial and COVID-19 drugs.

Natural flavonoids effectively block the CD81 receptor of hepatocytes and inhibit HCV infection: a computational drug development approach

Hepatitis C virus (HCV) infection is a major public health concern, and almost two million people are infected per year globally. This is occurred by the diverse spectrum of viral genotypes, which are directly associated with chronic liver disease (fibrosis, and cirrhosis). Indeed, the viral genome encodes three principal proteins as sequentially core, E1, and E2. Both E1 and E2 proteins play a crucial role in the attachment of the host system, but E2 plays a more fundamental role in attachment. The researchers have found the "E2-CD81 complex" at the entry site, and therefore, CD81 is the key receptor for HCV entrance in both humans, and chimpanzees. So, the researchers are trying to block the host CD81 receptor and halt the virus entry within the cellular system via plant-derived compounds. Perhaps that is why the current research protocol is designed to perform an in silico analysis of the flavonoid compounds for targeting the tetraspanin CD81 receptor of hepatocytes. To find out the best flavonoid compounds from our library, web-based tools (Swiss ADME, pKCSM), as well as computerized tools like the PyRx, PyMOL, BIOVIA Discovery Studio Visualizer, Ligplot+ V2.2, and YASARA were employed. For molecular docking studies, the flavonoid compounds docked with the targeted CD81 protein, and herein, the best-outperformed compounds are Taxifolin, Myricetin, Puerarin, Quercetin, and (-)-Epicatechin, and outstanding binding affinities are sequentially - 7.5, - 7.9, - 8.2, - 8.4, and - 8.5 kcal/mol, respectively. These compounds have possessed more interactions with the targeted protein. To validate the post docking data, we analyzed both 100 ns molecular dynamic simulation, and MM-PBSA via the YASARA simulator, and finally finds the more significant outcomes. It is concluded that in the future, these compounds may become one of the most important alternative antiviral agents in the fight against HCV infection. It is suggested that further in vivo, and in vitro research studies should be done to support the conclusions of this in silico research workflow.

Synthesis, antimicrobial, SAR, PASS, molecular docking, molecular dynamics and pharmacokinetics studies of 5'-O-uridine derivatives bearing acyl moieties: POM study and identification of the pharmacophore sites

Because of their superior antibacterial and pharmacokinetic capabilities, many nucleoside-based esters show potential against microorganisms, and may be used as pharmacological agents to address multidrug-resistant pathogenic problems. In this study, several aliphatic and aromatic groups were inserted to synthesize various 5'-O-decanoyluridine (2-5) and 5'-O-lauroyluridine derivatives (6-7) for antimicrobial, in silico computational, pharmacokinetic and POM (Petra/Osiris/Molinspiration). The chemical structures of the synthesized uridine derivatives were confirmed by physicochemical, elemental, and spectroscopic analyses. In vitro antimicrobial screening against five bacteria and two fungi, as well as the prediction of substance activity spectra (PASS), revealed that these uridine derivatives have promising antifungal properties when compared to the antibacterial activities. Density functional theory (DFT) was used to calculate the thermodynamic and physicochemical properties. Molecular docking was conducted against lanosterol 14a-demethylase CYP51A1 (3JUV) and Aspergillus flavus (1R4U) and revealed binding affinities and non-covalent interactions with the target. Then, a 150 ns molecular dynamic simulation was performed to confirm the behavior of the complex structure formed by microbial protein under in silico physiological conditions to examine its stability over time, which revealed a stable conformation and binding pattern in a stimulating environment of uridine derivatives. The acyl chain {CH₃(CH₂)₉CO-} and {CH₃(CH₂)₁₀CO-} in conjunction with sugar, was determined to have the most potent activity against bacterial and fungal pathogens in a structure-activity relationships (SAR) investigation. POM analyses were conducted with the presence of an antifungal (O ^δ- -- O' ^δ-) pharmacophore site. Overall, the present study might be useful for the development of uridine-based novel multidrug-resistant antimicrobial.

Comparative overview of emerging RNA viruses: Epidemiology, pathogenesis, diagnosis and current treatment

From many decades, emerging infections have threatened humanity. The pandemics caused by different CoVs have already claimed and will continue to claim millions of lives. The SARS, Ebola, MERS epidemics and the most recent emergence of COVID-19 pandemic have threatened populations across borders. Since a highly pathogenic CoV has been evolved into the human population in the twenty-first century known as SARS, scientific advancements and innovative methods to tackle these viruses have increased in order to improve response preparedness towards the unpredictable threat posed by these rapidly emerging pathogens. Recently published review articles on SARS-CoV-2 have mainly focused on its pathogenesis, epidemiology and available treatments. However, in this review, we have done a systematic comparison of all three CoVs i.e., SARS, MERS and SARS-CoV-2 along with Ebola and Zika in terms of their epidemiology, virology, clinical features and current treatment strategies. This review focuses on important emerging RNA viruses starting from Zika, Ebola and the CoVs which include SARS, MERS and SARS-CoV-2. Each of these viruses has been elaborated on the basis of their epidemiology, virulence, transmission and treatment. However, special attention has been given to SARS-CoV-2 and the disease caused by it i.e., COVID-19 due to current havoc caused worldwide. At the end, insights into the current understanding of the lessons learned from previous epidemics to combat emerging CoVs have been described. The travel-related viral spread, the unprecedented nosocomial outbreaks and the high case-fatality rates associated with these highly transmissible and pathogenic viruses highlight the need for new prophylactic and therapeutic actions which include but are not limited to clinical indicators, contact tracing, and laboratory investigations as important factors that need to be taken into account in order to arrive at the final conclusion.

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Recently published review articles on SARS-CoV-2 have mainly focused on its pathogenesis, epidemiology and available treatments.

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The pandemics caused by different CoVs have already claimed and will continue to claim millions of lives.

•

This review focuses on important emerging RNA viruses starting from Zika, Ebola and the CoVs which include SARS, MERS and SARS-CoV-2.

•

Globally, numerous studies and researchers have recently started fighting this virus.

Antiviral Peptides (AVPs) of Marine Origin as Propitious Therapeutic Drug Candidates for the Treatment of Human Viruses

The marine environment presents a favorable avenue for potential therapeutic agents as a reservoir of new bioactive natural products. Due to their numerous potential pharmacological effects, marine-derived natural products—particularly marine peptides—have gained considerable attention. These peptides have shown a broad spectrum of biological functions, such as antimicrobial, antiviral, cytotoxic, immunomodulatory, and analgesic effects. The emergence of new virus strains and viral resistance leads to continuing efforts to develop more effective antiviral drugs. Interestingly, antimicrobial peptides (AMPs) that possess antiviral properties and are alternatively regarded as antiviral peptides (AVPs) demonstrate vast potential as alternative peptide-based drug candidates available for viral infection treatments. Hence, AVPs obtained from various marine organisms have been evaluated. This brief review features recent updates of marine-derived AVPs from 2011 to 2021. Moreover, the biosynthesis of this class of compounds and their possible mechanisms of action are also discussed. Selected peptides from various marine organisms possessing antiviral activities against important human viruses—such as human immunodeficiency viruses, herpes simplex viruses, influenza viruses, hepatitis C virus, and coronaviruses—are highlighted herein.

Can the SARS-CoV-2 Omicron Variant Confer Natural Immunity against COVID-19?

The coronavirus disease 2019 (COVID-19) pandemic is still ongoing, with no signs of abatement in sight. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of this pandemic and has claimed over 5 million lives, is still mutating, resulting in numerous variants. One of the newest variants is Omicron, which shows an increase in its transmissibility, but also reportedly reduces hospitalization rates and shows milder symptoms, such as in those who have been vaccinated. As a result, many believe that Omicron provides a natural vaccination, which is the first step toward ending the COVID-19 pandemic. Based on published research and scientific evidence, we review and discuss how the end of this pandemic is predicted to occur as a result of Omicron variants being surpassed in the community. In light of the findings of our research, we believe that it is most likely true that the Omicron variant is a natural way of vaccinating the masses and slowing the spread of this deadly pandemic. While the mutation that causes the Omicron variant is encouraging, subsequent mutations do not guarantee that the disease it causes will be less severe. As the virus continues to evolve, humans must constantly adapt by increasing their immunity through vaccination.

Biochemical and Molecular Dynamics Study of a Novel GH 43 α-l-Arabinofuranosidase/β-Xylosidase From Caldicellulosiruptor saccharolyticus DSM8903

The complete hydrolysis of xylan can be facilitated by the coordinated action of xylanase and other de-branching enzymes. Here, a GH43 α-l-arabinofuranosidase/β-xylosidase (CAX43) from Caldicellulosiruptor saccharolyticus was cloned, sequenced, and biochemically investigated. The interaction of the enzyme with various substrates was also studied. With a half-life of 120 h at 70°C, the produced protein performed maximum activity at pH 6.0 and 70°C. The enzyme demonstrated a higher activity (271.062 ± 4.83 U/mg) against para nitrophenol (pNP) α-L-arabinofuranosides. With xylanase (XynA), the enzyme had a higher degree of synergy (2.30) in a molar ratio of 10:10 (nM). The interaction of the enzyme with three substrates, pNP α-L-arabinofuranosides, pNP β-D-xylopyranosides, and sugar beet arabinan, was investigated using protein modeling, molecular docking, and molecular dynamics (MD) simulation. During the simulation time, the root mean square deviation (RMSD) of the enzyme was below 2.5 Å, demonstrating structural stability. Six, five, and seven binding-interacting residues were confirmed against pNP α-L-arabinofuranosides, pNP β-D-xylopyranosides, and arabinan, respectively, in molecular docking experiments. This biochemical and in silico study gives a new window for understanding the GH43 family’s structural stability and substrate recognition, potentially leading to biological insights and rational enzyme engineering for a new generation of enzymes that perform better and have greater biorefinery utilization.

Fruit Bromelain-Derived Peptide Potentially Restrains the Attachment of SARS-CoV-2 Variants to hACE2: A Pharmacoinformatics Approach

Before entering the cell, the SARS-CoV-2 spike glycoprotein receptor-binding domain (RBD) binds to the human angiotensin-converting enzyme 2 (hACE2) receptor. Hence, this RBD is a critical target for the development of antiviral agents. Recent studies have discovered that SARS-CoV-2 variants with mutations in the RBD have spread globally. The purpose of this in silico study was to determine the potential of a fruit bromelain-derived peptide. DYGAVNEVK. to inhibit the entry of various SARS-CoV-2 variants into human cells by targeting the hACE binding site within the RBD. Molecular docking analysis revealed that DYGAVNEVK interacts with several critical RBD binding residues responsible for the adhesion of the RBD to hACE2. Moreover, 100 ns MD simulations revealed stable interactions between DYGAVNEVK and RBD variants derived from the trajectory of root-mean-square deviation (RMSD), radius of gyration (Rg), and root-mean-square fluctuation (RMSF) analysis, as well as free binding energy calculations. Overall, our computational results indicate that DYGAVNEVK warrants further investigation as a candidate for preventing SARS-CoV-2 due to its interaction with the RBD of SARS-CoV-2 variants.

Screening of Potent Phytochemical Inhibitors Against SARS-CoV-2 Main Protease: An Integrative Computational Approach

Coronavirus disease 2019 (COVID-19) is a potentially lethal and devastating disease that has quickly become a public health threat worldwide. Due to its high transmission rate, many countries were forced to implement lockdown protocols, wreaking havoc on the global economy and the medical crisis. The main protease (Mpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus for COVID-19, represent an effective target for the development of a new drug/vaccine because it is well-conserved and plays a vital role in viral replication. Mpro inhibition can stop the replication, transcription as well as recombination of SARS-CoV-2 after the infection and thus can halt the formation of virus particles, making Mpro a viable therapeutic target. Here, we constructed a phytochemical dataset based on a rigorous literature review and explored the probability that various phytochemicals will bind with the main protease using a molecular docking approach. The top three hit compounds, medicagol, faradiol, and flavanthrin, had binding scores of −8.3, −8.6, and −8.8 kcal/mol, respectively, in the docking analysis. These three compounds bind to the active groove, consisting of His41, Cys45, Met165, Met49, Gln189, Thr24, and Thr190, resulting in main protease inhibition. Moreover, the multiple descriptors from the molecular dynamics simulation, including the root-mean-square deviation, root-mean-square fluctuation, solvent-accessible surface area, radius of gyration, and hydrogen bond analysis, confirmed the stable nature of the docked complexes. In addition, absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis confirmed a lack of toxicity or carcinogenicity for the screened compounds. Our computational analysis may contribute toward the design of an effective drug against the main protease of SARS-CoV-2.