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COVID-19 is a severe acute respiratory syndrome caused by a novel coronavirus, SARS-CoV- 2.COVID-19 is now a pandemic, and is not yet fully under control.As the surface spike protein (S) mediates the recognition between the virus and cell membrane and the process of cell entry, it plays an important role in the course of disease transmission.The study on the S protein not only elucidates the structure and function of virus-related proteins and explains their cellular entry mechanism, but also provides valuable information for the prevention, diagnosis and treatment of COVII)-19.Concentrated on the S protein of SARS-CoV-2, this review covers four aspects: (1 ) The structure of the S protein and its binding with angiotensin converting enzyme II (ACE2) , the specific receptor of SARS-CoV-2, is introduced in detail.Compared with SARS-CoV, the receptor binding domain (RBD) of the SARS-CoV- 2 S protein has a higher affinity with ACE2, while the affinity of the entire S protein is on the contrary.(2) Currently, the cell entry mechanism of SARS-CoV-2 meditated by the S protein is proposed to include endosomal and non-endosomal pathways.With the recognition and binding between the S protein and ACE2 or after cell entry, transmembrane protease serine 2(TMPRSS2) , lysosomal cathepsin or the furin enzyme can cleave S protein at S1/S2 cleavage site, facilitating the fusion between the virus and target membrane.(3) For the progress in SARS-CoV-2 S protein antibodies, a collection of significant antibodies are introduced and compared in the fields of the target, source and type.(4) Mechanisms of therapeutic treatments for SARS-CoV-2 varied.Though the antibody and medicine treatments related to the SARS-CoV-2 S protein are of high specificity and great efficacy, the mechanism, safety, applicability and stability of some agents are still unclear and need further assessment.Therefore, to curb the pandemic, researchers in all fields need more cooperation in the development of SARS-CoV-2 antibodies and medicines to face the great challenge.Copyright © Palaeogeography (Chinese Edition).All right reserved.
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BackgroundUpadacitinib (UPA) is an oral JAK inhibitor (JAKi) approved for the treatment of RA. JAKi have been associated with an elevated risk of herpes zoster (HZ) in patients (pts) with RA. The adjuvanted recombinant zoster vaccine (RZV, Shingrix) was shown to be well-tolerated and effective in preventing HZ in adults aged ≥ 50 years.[1] The efficacy and safety of RZV have not been studied in pts with RA while on UPA in combination with MTX.ObjectivesTo assess the immunogenicity of RZV in pts with RA receiving UPA 15 mg once daily (QD) with background MTX.MethodsEligible adults aged ≥ 50 years with RA enrolled in the ongoing SELECT-COMPARE phase 3 trial (NCT02629159) received two RZV doses, administered at the baseline and week (wk) 12 visits. Pts should have been on stable doses of UPA 15 mg QD and background MTX for ≥ 8 wks before the first vaccination and ≥ 4 wks after the second vaccination. Antibody titers were collected pre-vaccination (baseline), 4 wks post-dose 1 vaccination (wk 4), and 4 wks post-dose 2 vaccination (wk 16). The primary endpoint was the proportion of pts with a humoral response to RZV defined as ≥ 4-fold increase in pre-vaccination concentration of anti-glycoprotein E [gE] titer levels at wk 16. Secondary endpoints included humoral response to RZV at wk 4 and the geometric mean fold rise (GMFR) in anti-gE antibody levels at wks 4 and 16. Cell-mediated immunogenicity to RZV was an exploratory endpoint evaluated by the frequencies of gE-specific CD4+ [2+] T cells (CD4+ T cells expressing ≥ 2 of 4 activation markers: IFN-γ, IL-2, TNF-α, and CD40 ligand) measured by flow cytometry at wks 4 and 16 in a sub-cohort of pts.ResultsOf the 95 pts who received ≥ 1 RZV dose, 93 (98%) received both RZV doses. Pts had a mean (standard deviation) age of 62.4 (7.5) years. The median (range) disease duration was 11.7 (4.9–41.6) years and duration of UPA exposure was 3.9 (2.9–5.8) years. At baseline, all but 2 pts were receiving concomitant MTX and half (50%) were taking an oral corticosteroid (CS) at a median daily dose of 5.0 mg. One pt discontinued UPA by wk 16. Blood samples were available from 90/93 pts. Satisfactory humoral responses to RZV occurred in 64% (95% confidence interval [CI]: 55–74) of pts at wk 4 and 88% (81–95) at wk 16 (Figure 1). Age (50–< 65 years: 85% [95% CI: 75–94];≥ 65 years: 94% [85–100]) and concomitant CS (yes: 87% [77–97];no: 89% [80–98]) use at baseline did not affect humoral responses at wk 16. GMFR in anti-gE antibody levels compared with baseline values were observed at wks 4 (10.2 [95% CI: 7.3–14.3]) and 16 (22.6 [15.9–32.2]). Among the sub-cohort of pts, nearly two-thirds achieved a cell-mediated immune response to RZV (wk 4: n = 21/34, 62% [95% CI: 45–78];wk 16: n = 25/38;66% [51–81]). Within 30 days post-vaccination of either RZV dose, no serious adverse events (AEs) (Table 1) or HZ were reported. AEs that were possibly related to RZV were reported in 17% of pts. One death occurred more than 30 days after wk 16 due to COVID-19 pneumonia.ConclusionMore than three-quarters (88%) of pts with RA receiving UPA 15 mg QD on background MTX achieved a satisfactory humoral response to RZV at wk 16. In a subgroup of pts, two-thirds (66%) achieved a cell-mediated immune response to RZV at wk 16. Age and concomitant CS use did not negatively affect RZV response.Reference[1]Syed YY. Drugs Aging. 2018;35:1031–40.Table 1. Safety Results Through 30-Days Post-RZV Vaccination in UPA-Treated PatientsEvent, n (%)UPA 15 mg QD (N = 95)Any AE38 (40%)AE with reasonable possibility of being related to UPAa13 (14%)AE with reasonable possibility of being related to RZVa16 (17%)Severe AEb1 (1%)Serious AE0AE leading to discontinuation of UPA0Death0AE, adverse event;QD, once daily;RZV, adjuvanted recombinant zoster vaccine;UPA, upadacitinib.aAs assessed by the investigator.bHypersensitivity.AcknowledgementsAbbVie funded this study and participated in the study design, research, analysis, data collection, interpretation of data, review, and approval of the . All authors had access to relevant data and participated in the drafting, review, and approval of this publication. No honoraria or payments were made for authorship. Medical writing support was provided by Julia Zolotarjova, MSc, MWC, of AbbVie.Disclosure of InterestsKevin Winthrop Consultant of: AbbVie, AstraZeneca, BMS, Eli Lilly, Galapagos, Gilead, GSK, Novartis, Pfizer, Regeneron, Roche, Sanofi, and UCB, Grant/research support from: AbbVie, AstraZeneca, BMS, Eli Lilly, Galapagos, Gilead, GSK, Novartis, Pfizer, Regeneron, Roche, Sanofi, and UCB, Justin Klaff Shareholder of: AbbVie, Employee of: AbbVie, Yanxi Liu Shareholder of: AbbVie, Employee of: AbbVie, CONRADO GARCIA GARCIA: None declared, Eduardo Mysler Speakers bureau: AbbVie, Amgen, AstraZeneca, BMS, Eli Lilly, GlaxoSmithKline, Pfizer, Roche, and Sandoz, Consultant of: AbbVie, Amgen, AstraZeneca, BMS, Eli Lilly, GlaxoSmithKline, Pfizer, Roche, and Sandoz, Alvin F. Wells Consultant of: AbbVie, Amgen, BMS, Eli Lilly, Novartis, Pfizer, and Sanofi, Xianwei Bu Shareholder of: AbbVie, Employee of: AbbVie, Nasser Khan Shareholder of: AbbVie, Employee of: AbbVie, Michael Chen Shareholder of: AbbVie, Employee of: AbbVie, Heidi Camp Shareholder of: AbbVie, Employee of: AbbVie, Anthony Cunningham Consultant of: GSK, Merck Sharp & Dohme, and BioCSL/Sequirus.
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Delivery of self-amplifying mRNA (SAM) has high potential for infectious disease vaccination due to its self-adjuvanting and dose-sparing properties. Yet a challenge is the susceptibility of SAM to degradation and the need for SAM to reach the cytosol fully intact to enable self-amplification. Lipid nanoparticles are successfully deployed at incredible speed for mRNA vaccination, but aspects such as cold storage, manufacturing, efficiency of delivery, and the therapeutic window can benefit from further improvement. To investigate alternatives to lipid nanoparticles, a class of >200 biodegradable end-capped lipophilic poly(beta-amino ester)s (PBAEs) that enable efficient delivery of SAM in vitro and in vivo as assessed by measuring expression of SAM encoding reporter proteins is developed. The ability of these polymers to deliver SAM intramuscularly in mice is evaluated, and a polymer-based formulation that yields up to 37-fold higher intramuscular (IM) expression of SAM compared to injected naked SAM is identified. Using the same nanoparticle formulation to deliver a SAM encoding rabies virus glycoprotein, the vaccine elicits superior immunogenicity compared to naked SAM delivery, leading to seroconversion in mice at low RNA injection doses. These biodegradable nanomaterials may be useful in the development of next-generation RNA vaccines for infectious diseases.Copyright © 2023 The Authors. Advanced Therapeutics published by Wiley-VCH GmbH.
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The aim of this study was to evaluate the impact of the most frequent Asn501 polar uncharged amino acid mutations upon important structural properties of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) Surface Glycoprotein RBD–hACE2 (human angiotensin-converting enzyme 2) heterodimer. Mutations N501Y, N501T and N501S were considered and their impact upon complex solubility, secondary motifs formation and intermolecular hydrogen bonding interface was analyzed. Results and findings are reported based on 50 ns run in Gromacs molecular dynamics simulation software. Special attention is paid on the biomechanical shifts in the receptor-binding domain (RBD) [499-505]: ProThrAsn(Tyr)GlyValGlyTyr, having substituted Asparagine to Tyrosine at position 501. The main findings indicate that the N501S mutation increases SARS-CoV-2 S-protein RBD–hACE2 solubility over N501T, N501 (wild type): (Formula presented.), (Formula presented.). The N501Y mutation shifts (Formula presented.) -helix S-protein RBD [366-370]: SerValLeuTyrAsn into π-helix for t > 38.5 ns. An S-protein RBD [503-505]: ValGlyTyr shift from (Formula presented.) -helix into a turn is observed due to the N501Y mutation in t > 33 ns. An empirical proof for the presence of a Y501-binding pocket, based on RBD [499-505]: PTYGVGY (Formula presented.) 's RMSF peak formation is presented. There is enhanced electrostatic interaction between Tyr505 (RBD) phenolic -OH group and Glu37 (hACE2) side chain oxygen atoms due to the N501Y mutation. The N501Y mutation shifts the (Formula presented.) hydrogen bond into permanent polar contact;(Formula presented.);(Formula presented.). © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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OBJECTIVE: Jingfang Granules have been recommended for the prevention and treatment of corona virus disease 2019 (COVID-19). Through chemical analysis and bioactivity evaluation, this study aims to elucidate the potential effective components of Jingfang Granules. METHOD(S): The inhibitory acti-vities of Jingfang Granules extract against 3-chymotrypsin-like protease (3CLpro), papain like protease (PLpro), spike protein receptor-binding domain (S-RBD) and human cyclooxygenase-2 (COX-2) were evaluated using enzyme assay. The antitussive effects were evaluated using the classical ammonia-induced cough model. The chemical constituents of Jingfang Granules were qualitatively and quantitatively analyzed by liquid chromatography-mass spectrometry (LC/MS). The 3CLpro and PLpro inhibitory activities of the major compounds were determined by enzyme assay, molecular docking, and site-directed mutagenesis. RESULT(S): Jingfang Granules exhibited 3CLpro and PLpro inhibitory activities, as well as COX-2 inhibitory and antitussive activities. By investigating the MS/MS behaviors of reference standards, a total of fifty-six compounds were characterized in Jingfang Granules. Sixteen of them were unambiguously identified by comparing with reference standards. The contents of the 16 major compounds were also determined, and their total contents were 2 498.8 mug/g. Naringin, nodakenin and neohesperidin were three dominating compounds in Jingfang Granules, and their contents were 688.8, 596.4 and 578.7 mug/g, respectively. In addition, neohesperidin and naringin exhibited PLpro inhibitory activities, and the inhibition rates at 8 mumol/L were 53.5% and 46.1%, respectively. Prim-O-glucosylcimifugin showed significant inhibitory activities against 3CLpro and PLpro, and the inhibitory rates at 8 mumol/L were 76.8% and 78.2%, respectively. Molecular docking indicated that hydrogen bonds could be formed between prim-O-glucosylcimifugin and amino acid residues H163, E166, Q192, T190 of 3CLpro (binding energy, -7.7 kcal/mol) and K157, D164, R166, E167, T301 of PLpro(-7.3 kcal/mol), respectively. Site-directed mutagenesis indicated amino acid residue K157 was a key active site for the interaction between prim-O-glucosylcimifugin and PLpro. CONCLUSION(S): Prim-O-glucosylcimifugin, neohesperidin, and naringin as the major compounds from Jingfang Granules could inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus proteases 3CLpro and PLpro. The results are valuable for rational clinical use of Jingfang Granules.
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Monitoring of the proportion of immune individuals and the effectiveness of vaccination in a population involves evaluation of several important parameters, including the level of virus-neutralising antibodies. In order to combat the COVID-19 pandemic, it is essential to develop approaches to detecting SARS-CoV-2 neutralising antibodies by safe, simple and rapid methods that do not require live viruses. To develop a test system for enzyme-linked immunosorbent assay (ELISA) that detects potential neutralising antibodies, it is necessary to obtain a highly purified recombinant receptor-binding domain (RBD) of the spike (S) protein with high avidity for specific antibodies. The aim of the study was to obtain and characterise a SARSCoV-2 S-protein RBD homodimer and a recombinant RBD-expressing cell line, as well as to create an ELISA system for detecting potential neutralising antibodies. Material(s) and Method(s): the genetic construct was designed in silico. To generate a stable producer cell line, the authors transfected CHO-S cells, subjected them to antibiotic pressure, and selected the optimal clone. To isolate monomeric and homodimeric RBD forms, the authors purified the recombinant RBD by chromatographic methods. Further, they analysed the activity of the RBD forms by Western blotting, bio-layer interferometry, and indirect ELISA. The analysis involved monoclonal antibodies GamXRH19, GamP2C5, and h6g3, as well as serum samples from volunteers vaccinated with Gam-COVID-Vac (Sputnik V) and unvaccinated ones. Result(s): the authors produced the CHO-S cell line for stable expression of the recombinant SARS-CoV-2 S-protein RBD. The study demonstrated the recombinant RBD's ability to homodimerise after fed-batch cultivation of the cell line for more than 7 days due to the presence of unpaired cysteines. The purified recombinant RBD yield from culture broth was 30-50 mg/L. Monomeric and homodimeric RBD forms were separated using gel-filtration chromatography and characterised by their ability to interact with specific monoclonal antibodies, as well as with serum samples from vaccinated volunteers. The homodimeric recombinant RBD showed increased avidity for both monoclonal and immune sera antibodies. Conclusion(s): the homodimeric recombinant RBD may be more preferable for the analysis of levels of antibodies to the receptor-binding domain of the SARS-CoV-2 S protein.Copyright © 2023 Authors. All rights reserved.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the cause of coronavirus disease 2019 (COVID-19), has affected millions of people globally. It is a very contagious disease with various clinical manifestations. However, even in asymptomatic patients, it is believed that this virus exposure induces cryptic antibodies as in symptomatic patients. This current study aims to assess the prevalence of SARS-CoV-2 seropositivity by detecting the antibodies specific to the receptor-binding domain (SRBD) of SARS-CoV-2 in the pre-vaccine population in Bali. We assessed specific antibody titers against trimeric spike glycoprotein (S) of SARS-CoV-2 using Roche Elecsys Anti-SARS-CoV-2 S immunoassay in the serum of 510 pre-vaccine subjects without a previous documented history of SARS-CoV-2 infection. The average age was 35.53 years with 56.7% of the subjects being male. Among 510 subjects, 190 (37.3%) subjects were detected to have SARS-CoV-2 SRBD antibody or be seropositive. The range of the antibody titer was zero to 250 U/mL with the average being 44.3 U/mL. The number of subjects who had anti-SARS-Cov-2 SRBD titer above 132 U/mL was 76 (14.9%);it was the minimal antibody titer needed to donate plasma for plasma convalescent therapy. This study revealed a pre-vaccination population, without a history of COVID-19 infection, with seropositivity to SARS-CoV-2, which indicates the underdiagnosis of COVID-19, especially in asymptomatic individuals.
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The coronavirus disease (COVID-19) pandemic has rapidly extended globally and killed approximately 5.83 million people all over the world. But, to date, no effective therapeutic against the disease has been developed. The disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and enters the host cell through the spike glycoprotein (S protein) of the virus. Subsequently, RNA-dependent RNA polymerase (RdRp) and main protease (Mpro) of the virus mediate viral transcription and replication. Mechanistically inhibition of these proteins can hinder the transcription as well as replication of the virus. Recently oxysterols and its derivative, such as 25 (S)-hydroxycholesterol (25-HC) has shown antiviral activity against SARS-CoV-2. But the exact mechanisms and their impact on RdRp and Mpro have not been explored yet. Therefore, the study aimed to identify the inhibitory activity of 25-HC against the viral enzymes RdRp and Mpro simultaneously. Initially, a molecular docking simulation was carried out to evaluate the binding activity of the compound against the two proteins. The pharmacokinetics (PK) and toxicity parameters were analyzed to observe the 'drug-likeness' properties of the compound. Additionally, molecular dynamics (MD) simulation was performed to confirm the binding stability of the compound to the targeted protein. Furthermore, molecular mechanics generalized Born surface area (MM-GBSA) was used to predict the binding free energies of the compound to the targeted protein. Molecular docking simulation identified low glide energy -51.0 kcal/mol and -35.0 kcal/mol score against the RdRp and Mpro, respectively, where MD simulation found good binding stability of the compound to the targeted proteins. In addition, the MM/GBSA approach identified a good value of binding free energies (ΔG bind) of the compound to the targeted proteins. Therefore, the study concludes that the compound 25-HC could be developed as a treatment and/or prevention option for SARS-CoV-2 disease-related complications. Although, experimental validation is suggested for further evaluation of the work.Communicated by Ramaswamy H. Sarma.
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Complete coverage of all N-glycosylation sites on the SARS-CoV2 spike protein would require the use of multiple proteases in addition to trypsin. Subsequent identification of the resulting glycopeptides by searching against database often introduces assignment errors due to similar mass differences between different permutations of amino acids and glycosyl residues. By manually interpreting the individual MS2 spectra, we report here the common sources of errors in assignment, especially those introduced by the use of chymotrypsin. We show that by applying a stringent threshold of acceptance, erroneous assignment by the commonly used Byonic software can be controlled within 15%, which can be reduced further if only those also confidently identified by a different search engine, pGlyco3, were considered. A representative site-specific N-glycosylation pattern could be constructed based on quantifying only the overlapping subset of N-glycopeptides identified at higher confidence. Applying the two complimentary glycoproteomic software in a concerted data analysis workflow, we found and confirmed that glycosylation at several sites of an unstable Omicron spike protein differed significantly from those of the stable trimeric product of the parental D614G variant.
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<b>Background and Objective:</b> The COVID-19, which has been circulating since late 2019, is caused by SARS-CoV-2. Because of its high infectivity, this virus has spread widely throughout the world. Spike glycoprotein is one of the proteins found in SARS-CoV-2. Spike glycoproteins directly affect infection by forming ACE-2 receptors on host cells. Inhibiting glycoprotein spikes could be one method of treating COVID-19. In this study, the antivirus marketed as a database will be repurposed into an antiviral SARS-CoV-2 and the selected compounds will be modified to become organoselenium compounds. <b>Materials and Methods:</b> The research was carried out using <i>in silico</i> methods, such as rigid docking and flexible docking. To obtain information about the interaction between spike glycoprotein and ligands, MOE 2014.09 was used to perform the molecular docking simulation. <b>Results:</b> The analysis of binding energy values was used to select the ten best ligands from the first stage of the molecular docking simulation, which was then modified according to the previous QSAR study to produce 96 new molecules. The second stage of molecular docking simulation was performed with modified molecules. The best-modified ligand was chosen by analyzing the ADME-Tox property, RMSD value and binding energy value. <b>Conclusion:</b> The best three unmodified ligands, Ombitasvir, Elbasvir and Ledipasvir, have a binding energy value of -15.8065, -15.3842 and -15.1255 kcal mol<sup>1</sup>, respectively and the best three modified ligands ModL1, ModL2 and ModL3 has a binding value of -15.6716, -13.9489 and -13.2951 kcal mol<sup>1</sup>, respectively with an RMSD value of 1.7109 Å, 2.3179 Å and 1.7836 Å.
Subject(s)
COVID-19 , Organoselenium Compounds , Humans , SARS-CoV-2 , Ligands , Molecular Docking Simulation , Antiviral Agents/pharmacology , Molecular Dynamics SimulationABSTRACT
The antiviral benefit of antibodies can be compromised by viral escape especially for rapidly evolving viruses. Therefore, durable, effective antibodies must be both broad and potent to counter newly emerging, diverse strains. Discovery of such antibodies is critically important for SARS-CoV-2 as the global emergence of new variants of concern (VOC) has compromised the efficacy of therapeutic antibodies and vaccines. We describe a collection of broad and potent neutralizing monoclonal antibodies (mAbs) isolated from an individual who experienced a breakthrough infection with the Delta VOC. Four mAbs potently neutralize the Wuhan-Hu-1 vaccine strain, the Delta VOC, and also retain potency against the Omicron VOCs through BA.4/BA.5 in both pseudovirus-based and authentic virus assays. Three mAbs also retain potency to recently circulating VOCs XBB.1.5 and BQ.1.1 and one also potently neutralizes SARS-CoV-1. The potency of these mAbs was greater against Omicron VOCs than all but one of the mAbs that had been approved for therapeutic applications. The mAbs target distinct epitopes on the spike glycoprotein, three in the receptor-binding domain (RBD) and one in an invariant region downstream of the RBD in subdomain 1 (SD1). The escape pathways we defined at single amino acid resolution with deep mutational scanning show they target conserved, functionally constrained regions of the glycoprotein, suggesting escape could incur a fitness cost. Overall, these mAbs are unique in their breadth across VOCs, their epitope specificity, and include a highly potent mAb targeting a rare epitope outside of the RBD in SD1.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Breakthrough Infections , Antibodies, Monoclonal , Antibodies, Neutralizing , Epitopes , Spike Glycoprotein, Coronavirus/genetics , Antibodies, ViralABSTRACT
Baricitinib is a Janus Kinase (JAK) inhibitor that is primarily used to treat moderately to severely active rheumatoid arthritis in adults and has recently been reported for the treatment of patients with severe COVID-19. This paper describes the investigation of the binding behavior of baricitinib to human α1-acid glycoprotein (HAG) employing a variety of spectroscopic techniques, molecular docking and dynamics simulations. Baricitinib can quench the fluorescence from amino acids in HAG through a mix of dynamic and static quenching, according to steady-state fluorescence and UV spectra observations, but it is mainly static quenching at low concentration. The binding constant (Kb) of baricitinib to HAG at 298 K was at the level of 104 M-1, indicating a moderate affinity of baricitinib to HAG. Hydrogen bonding and hydrophobic interactions conducted the main effect, according to thermodynamic characteristics, competition studies between ANS and sucrose, and molecular dynamics simulations. For the change in HAG conformation, the results of multiple spectra showed that baricitinib was able to alter the secondary structure of HAG as well as increase the polarity of the microenvironment around the Trp amino acid. Furthermore, the binding behavior of baricitinib to HAG was investigated by molecular docking and molecular dynamics simulations, which validated experimental results. Also explored is the influence of K+, Co2+, Ni2+, Ca2+, Fe3+, Zn2+, Mg2+ and Cu2+plasma on binding affinity.
Subject(s)
COVID-19 , Janus Kinase Inhibitors , Humans , Molecular Docking Simulation , Protein Binding , Orosomucoid/chemistry , COVID-19 Drug Treatment , Molecular Dynamics Simulation , Protein Structure, Secondary , Thermodynamics , Binding Sites , Spectrometry, FluorescenceABSTRACT
Histidine-rich glycoprotein (HRG) is a liver-produced protein circulating in human serum at high concentrations of around 125 µg/ml. HRG belongs to the family of type-3 cystatins and has been implicated in a plethora of biological processes, albeit that its precise function is still not well understood. Human HRG is a highly polymorphic protein, with at least five variants with minor allele frequencies of more than 10%, variable in populations from different parts of the world. Considering these five mutations we can theoretically expect 35 = 243 possible genetic HRG variants in the population. Here, we purified HRG from serum of 44 individual donors and investigated by proteomics the occurrence of different allotypes, each being either homozygote or heterozygote for each of the five mutation sites. We observed that some mutational combinations in HRG were highly favored, while others were apparently missing, although they ought to be present based on the independent assembly of these five mutation sites. To further explore this behavior, we extracted data from the 1000 genome project (n â¼ 2500 genomes) and assessed the frequency of different HRG mutants in this larger dataset, observing a prevailing agreement with our proteomics data. From all the proteogenomic data we conclude that the five different mutation sites in HRG are not occurring independently, but several mutations at different sites are fully mutually exclusive, whereas others are highly intwined. Specific mutations do also affect HRG glycosylation. As the levels of HRG have been suggested as a protein biomarker in a variety of biological processes (e.g., aging, COVID-19 severity, severity of bacterial infections), we here conclude that the highly polymorphic nature of the protein needs to be considered in such proteomics evaluations, as these mutations may affect HRG's abundance, structure, posttranslational modifications, and function.
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Continued evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is eroding antibody responses elicited by prior vaccination and infection. The SARS-CoV-2 receptor-binding domain (RBD) E406W mutation abrogates neutralization mediated by the REGEN-COV therapeutic monoclonal antibody (mAb) COVID-19 cocktail and the AZD1061 (COV2-2130) mAb. Here, we show that this mutation remodels the receptor-binding site allosterically, thereby altering the epitopes recognized by these three mAbs and vaccine-elicited neutralizing antibodies while remaining functional. Our results demonstrate the spectacular structural and functional plasticity of the SARS-CoV-2 RBD, which is continuously evolving in emerging SARS-CoV-2 variants, including currently circulating strains that are accumulating mutations in the antigenic sites remodeled by the E406W substitution.
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COVID-19, caused by the novel SARS-CoV-2 virus, poses major challenges for global public health. The detection of antibodies in blood serum is one of the important methods for diagnostics of COVID-19 patients. The main aim was to study the dynamics of the appearance of neutralizing antibodies and antibodies to the SARS-CoV-2 proteins in COVID-19 patients sera. Material and methods. The blood sera of four groups of people were studied: "intact" donors (blood sera were collected in 2016-2019);patients with a laboratory-confirmed diagnosis of acute respiratory viral infection;patients with influenza (antibodies to the influenza virus have been identified) and patients with a PCR confirmed diagnosis of COVID-19. Blood sera were analyzed in ELISA with commercial kits for detection of IgG to SARS-CoV-2 (N, S) proteins and total antibodies to RBD of protein S and in neutralization test (NT). Results and discussion. Antibodies to SARS-CoV-2 were not detected in paired blood sera of people from groups 1-3 by ELISA and NT. At the time of hospitalization of patients with COVID-19 in the sera of 12 (19%) patients antibodies to SARS-CoV-2 were absent when they were determined by NT and ELISA. In blood sera taken 4-9 days after hospitalization, neutralizing antibodies and antibodies to at least one viral protein were detected in ELISA. Conclusion. At the time of hospitalization, the overwhelming majority of patients had a humoral immune response to the SARS-CoV-2. In the dynamics of observation, the levels of antibodies to SARS-CoV-2 proteins increased, to a greater extent to RBD.Copyright © 2022 Geotar Media Publishing Group
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As the fight against SARS-CoV-2 remains undefeated despite available vaccines, continuous efforts to curtail this deadly and highly spreading virus remain a world priority. In this research, we have investigated the antiviral properties of the phytochemicals from Annona muricata (Sour Sop) as potential inhibitors of SARS-CoV-2 main protease (Mpro) and Spike Receptor Protein. Pharmacokinetic analyses such as in-silicoADME, drug-likeness, PASS prediction, oral-bioavailability and bioactivity were carried out to screen the phytochemicals, 9 out of the 131 ligands satisfied the screening. A molecular docking approach was used to obtain the binding energies of the 9 ligands, and the result showed that Roseoside (-7.50 » kcal/mol) and Coreximine (-7.0 » kcal/mol) displayed the best docking score and have predicted to have stable interactions with SARS-CoV-2 main protease and Spike Glycoprotein. Data from this study could be further explored in developing multi-target drugs against SARS-CoV-2. © 2023 Walter de Gruyter GmbH, Berlin/Boston 2023.
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Intro: The COVID-19 pandemic is caused by the SARS-CoV-2 virus, an enveloped RNA of the coronavirus family. The advancement in molecular technology and biochemistry has accelerated the development of diagnostic reagents and assays. Much attention has been focused on the S protein, but the high mutation rate in this region could lead to false negative results. Thus, a better target protein for diagnostic application is needed for accurate detection. Method(s): Nucleotide sequences encoded for membrane (M) glycoprotein gene region of SARS-CoV-2 from Malaysian isolates were extracted from GISAID, aligned, and selected accordingly. The DNA plasmid was commercially synthesized with codon optimization for Escherichia coli (E. coli), and the presence of the M gene was confirmed by PCR. The plasmid was then transformed into E. coli. Later, the expression of M glycoprotein was induced, separated on an SDS-PAGE gel, and transferred onto a nitrocellulose membrane, followed by immunostaining. Finding(s): The analysis of the M glycoprotein against the Omicron strains demonstrated that the amino acid is conserved (99.5%). The M glycoprotein was successfully expressed and detected with antibodies from SARS-CoV-2 infected patients at ~26 kDa. The protein is currently upscale for the generation of monoclonal Ab (Mab). Discussion(s): The M protein of SARS-CoV-2 is more conserved among the virus and also has been reported to confer antigenic properties. Selection of M protein perhaps a better option compared to current detection assays that use spike (S) protein, which could lead to false negative results, as this gene region particularly the ribosome-binding domain (RBD) rapidly undergoes mutations. The utilization of M protein potentially improves negative predictive value (NPV) of the diagnostic test. Conclusion(s): Further development of diagnostic reagents is needed to improve the assay's specificity. The newly developed M protein and the MAb can be used to generate a more accurate viral detection assay.Copyright © 2023
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Viral envelope glycoproteins are crucial for viral infections. In the process of enveloped viruses budding and release from the producer cells, viral envelope glycoproteins are presented on the viral membrane surface as spikes, promoting the virus's next-round infection of target cells. However, the host cells evolve counteracting mechanisms in the long-term virus-host co-evolutionary processes. For instance, the host cell antiviral factors could potently suppress viral replication by targeting their envelope glycoproteins through multiple channels, including their intracellular synthesis, glycosylation modification, assembly into virions, and binding to target cell receptors. Recently, a group of studies discovered that some host antiviral proteins specifically recognized host proprotein convertase (PC) furin and blocked its cleavage of viral envelope glycoproteins, thus impairing viral infectivity. Here, in this review, we briefly summarize several such host antiviral factors and analyze their roles in reducing furin cleavage of viral envelope glycoproteins, aiming at providing insights for future antiviral studies.