Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 52
Filter
1.
Int J Mol Sci ; 22(21)2021 Oct 28.
Article in English | MEDLINE | ID: covidwho-1488613

ABSTRACT

The renin-angiotensin system (RAS) is a key regulator of blood pressure and hypertension. Angiotensin-converting enzyme 2 (ACE2) and angiotensin-converting enzyme I (ACE) are two main components of the RAS that play a major role in blood pressure homeostasis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses ACE2 as a receptor to enter cells. Despite some controversies, numerous studies have reported a significant association between the use of ACE inhibitors and reduced risk of COVID-19. In our previous studies, we produced and identified peptide sequences present in whey hydrolysates exhibiting high ACE inhibitory activity. Therefore, the aim of this work is to obtain an improved understanding of the function of these natural peptides as RAS inhibitors and investigate their potential therapeutic role in the COVID-19 pandemic. The molecular interactions between peptides IPP, LIVTQ, IIAE, LVYPFP, and human ACE2 were assessed by employing a molecular docking approach. The results show that natural whey-derived peptides have a dual inhibitory action against both ACE and ACE2. This dual activity distinguishes these ACE inhibitory peptides from synthetic drugs, such as Captopril and Lisinopril which were not shown to inhibit ACE2 activity, and may represent a potential strategy in the treatment of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19 , Peptides/chemistry , Peptides/pharmacology , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme Inhibitors/chemistry , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , COVID-19/drug therapy , Humans , Molecular Docking Simulation , Peptides/metabolism , Peptidyl-Dipeptidase A/chemistry , Renin-Angiotensin System/drug effects , Whey Proteins/chemistry
2.
Molecules ; 26(20)2021 Oct 13.
Article in English | MEDLINE | ID: covidwho-1470934

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2, the causative agent of coronavirus disease (COVID-19)) has caused relatively high mortality rates in humans throughout the world since its first detection in late December 2019, leading to the most devastating pandemic of the current century. Consequently, SARS-CoV-2 therapeutic interventions have received high priority from public health authorities. Despite increased COVID-19 infections, a vaccine or therapy to cover all the population is not yet available. Herein, immunoinformatics and custommune tools were used to identify B and T-cells epitopes from the available SARS-CoV-2 sequences spike (S) protein. In the in silico predictions, six B cell epitopes QTGKIADYNYK, TEIYQASTPCNGVEG, LQSYGFQPT, IRGDEVRQIAPGQTGKIADYNYKLPD, FSQILPDPSKPSKRS and PFAMQMAYRFNG were cross-reacted with MHC-I and MHC-II T-cells binding epitopes and selected for vaccination in experimental animals for evaluation as candidate vaccine(s) due to their high antigenic matching and conserved score. The selected six peptides were used individually or in combinations to immunize female Balb/c mice. The immunized mice raised reactive antibodies against SARS-CoV-2 in two different short peptides located in receptor binding domain and S2 region. In combination groups, an additive effect was demonstrated in-comparison with single peptide immunized mice. This study provides novel epitope-based peptide vaccine candidates against SARS-CoV-2.


Subject(s)
COVID-19 Vaccines/chemistry , COVID-19/prevention & control , Epitopes, B-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/chemistry , SARS-CoV-2/metabolism , Amino Acid Sequence , Animals , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/virology , COVID-19 Vaccines/administration & dosage , Epitopes, B-Lymphocyte/immunology , Epitopes, B-Lymphocyte/metabolism , Epitopes, T-Lymphocyte/immunology , Epitopes, T-Lymphocyte/metabolism , Female , Humans , Immunization , Mice , Mice, Inbred BALB C , Peptides/chemistry , Peptides/immunology , Peptides/metabolism , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
3.
Int J Mol Sci ; 22(20)2021 Oct 18.
Article in English | MEDLINE | ID: covidwho-1470894

ABSTRACT

Infection caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) in many cases is accompanied by the release of a large amount of proinflammatory cytokines in an event known as "cytokine storm", which is associated with severe coronavirus disease 2019 (COVID-19) cases and high mortality. The excessive production of proinflammatory cytokines is linked, inter alia, to the enhanced activity of receptors capable of recognizing the conservative regions of pathogens and cell debris, namely TLRs, TREM-1 and TNFR1. Here we report that peptides derived from innate immunity protein Tag7 inhibit activation of TREM-1 and TNFR1 receptors during acute inflammation. Peptides from the N-terminal fragment of Tag7 bind only to TREM-1, while peptides from the C-terminal fragment interact solely with TNFR1. Selected peptides are capable of inhibiting the production of proinflammatory cytokines both in peripheral blood mononuclear cells (PBMCs) from healthy donors and in vivo in the mouse model of acute lung injury (ALI) by diffuse alveolar damage (DAD). Treatment with peptides significantly decreases the infiltration of mononuclear cells to lungs in animals with DAD. Our findings suggest that Tag7-derived peptides might be beneficial in terms of the therapy or prevention of acute lung injury, e.g., for treating COVID-19 patients with severe pulmonary lesions.


Subject(s)
Acute Lung Injury/pathology , Cytokines/chemistry , Peptides/metabolism , Receptors, Tumor Necrosis Factor, Type I/metabolism , Triggering Receptor Expressed on Myeloid Cells-1/metabolism , Acute Lung Injury/metabolism , Animals , Cytokines/genetics , Cytokines/metabolism , Disease Models, Animal , Humans , Interferon-gamma/genetics , Interferon-gamma/metabolism , Leukocytes, Mononuclear/cytology , Leukocytes, Mononuclear/drug effects , Leukocytes, Mononuclear/metabolism , Lipopolysaccharides/pharmacology , Lung/metabolism , Lung/pathology , Lymphocyte Activation/drug effects , Male , Mice , Mice, Inbred ICR , Peptides/chemistry , Peptides/pharmacology , Protein Binding , Receptors, Tumor Necrosis Factor, Type I/antagonists & inhibitors , Triggering Receptor Expressed on Myeloid Cells-1/antagonists & inhibitors
4.
J Immunol ; 207(10): 2521-2533, 2021 11 15.
Article in English | MEDLINE | ID: covidwho-1468558

ABSTRACT

Many patients with coronavirus disease 2019 in intensive care units suffer from cytokine storm. Although anti-inflammatory therapies are available to treat the problem, very often, these treatments cause immunosuppression. Because angiotensin-converting enzyme 2 (ACE2) on host cells serves as the receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), to delineate a SARS-CoV-2-specific anti-inflammatory molecule, we designed a hexapeptide corresponding to the spike S1-interacting domain of ACE2 receptor (SPIDAR) that inhibited the expression of proinflammatory molecules in human A549 lung cells induced by pseudotyped SARS-CoV-2, but not vesicular stomatitis virus. Accordingly, wild-type (wt), but not mutated (m), SPIDAR inhibited SARS-CoV-2 spike S1-induced activation of NF-κB and expression of IL-6 and IL-1ß in human lung cells. However, wtSPIDAR remained unable to reduce activation of NF-κB and expression of proinflammatory molecules in lungs cells induced by TNF-α, HIV-1 Tat, and viral dsRNA mimic polyinosinic-polycytidylic acid, indicating the specificity of the effect. The wtSPIDAR, but not mutated SPIDAR, also hindered the association between ACE2 and spike S1 of SARS-CoV-2 and inhibited the entry of pseudotyped SARS-CoV-2, but not vesicular stomatitis virus, into human ACE2-expressing human embryonic kidney 293 cells. Moreover, intranasal treatment with wtSPIDAR, but not mutated SPIDAR, inhibited lung activation of NF-κB, protected lungs, reduced fever, improved heart function, and enhanced locomotor activities in SARS-CoV-2 spike S1-intoxicated mice. Therefore, selective targeting of SARS-CoV-2 spike S1-to-ACE2 interaction by wtSPIDAR may be beneficial for coronavirus disease 2019.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Anti-Inflammatory Agents/therapeutic use , COVID-19/therapy , Lung/immunology , Peptides/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , A549 Cells , Angiotensin-Converting Enzyme 2/genetics , Animals , COVID-19/immunology , Cytokines/metabolism , Female , HEK293 Cells , Humans , Inflammation Mediators/metabolism , Locomotion , Male , Mice , Molecular Targeted Therapy , NF-kappa B/metabolism , Peptides/genetics , Peptides/therapeutic use , Signal Transduction , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
5.
Front Immunol ; 12: 725240, 2021.
Article in English | MEDLINE | ID: covidwho-1463472

ABSTRACT

Ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus strains is posing new COVID-19 diagnosis and treatment challenges. To help efforts to meet these challenges we examined data acquired from proteomic analyses of human SARS-CoV-2-infected cell lines and samples from COVID-19 patients. Initially, 129 unique peptides were identified, which were rigorously evaluated for repeats, disorders, polymorphisms, antigenicity, immunogenicity, toxicity, allergens, sequence similarity to human proteins, and contributions from other potential cross-reacting pathogenic species or the human saliva microbiome. We also screened SARS-CoV-2-infected NBHE and A549 cell lines for presence of antigenic peptides, and identified paratope peptides from crystal structures of SARS-CoV-2 antigen-antibody complexes. We then selected four antigen peptides for docking with known viral unbound T-cell receptor (TCR), class I and II peptide major histocompatibility complex (pMHC), and identified paratope sequences. We also tested the paratope binding affinity of SARS-CoV T- and B-cell peptides that had been previously experimentally validated. The resultant antigenic peptides have high potential for generating SARS-CoV-2-specific antibodies, and the paratope peptides can be directly used to develop a COVID-19 diagnostics assay. The presented genomics and proteomics-based in-silico approaches have apparent utility for identifying new diagnostic peptides that could be used to fight SARS-CoV-2.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/metabolism , Epitopes, B-Lymphocyte/metabolism , Epitopes, T-Lymphocyte/metabolism , Peptides/metabolism , Pulmonary Alveoli/pathology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , A549 Cells , COVID-19/immunology , Cell Line , Coronavirus Nucleocapsid Proteins/genetics , Epitope Mapping , Epitopes, B-Lymphocyte/genetics , Epitopes, T-Lymphocyte/genetics , HLA Antigens/metabolism , Humans , Molecular Docking Simulation , Peptides/genetics , Phosphoproteins/genetics , Phosphoproteins/metabolism , Protein Binding , Proteomics , Receptors, Antigen/metabolism , Spike Glycoprotein, Coronavirus/genetics
6.
Front Immunol ; 12: 707977, 2021.
Article in English | MEDLINE | ID: covidwho-1457901

ABSTRACT

The ongoing COVID-19 pandemic caused by SARS-CoV-2 is a huge public health crisis for the globe. The receptor-binding domain (RBD) of SARS-CoV-2 spike (S) protein plays a vital role in viral infection and serves as a major target for developing neutralizing antibodies. In this study, the antibody response to the RBD of SARS-CoV-2 S protein was analyzed by a panel of sera from animals immunized with RBD-based antigens and four linear B-cell epitope peptides (R345, R405, R450 and R465) were revealed. The immunogenicity of three immunodominant peptides (R345, R405, R465) was further accessed by peptide immunization in mice, and all of them could induced potent antibody response to SARS-CoV-2 S protein, indicating that the three determinants in the RBD were immunogenic. We further generated and characterized monoclonal antibodies (15G9, 12C10 and 10D2) binding to these epitope peptides, and finely mapped the three immunodominant epitopes using the corresponding antibodies. Neutralization assays showed that all three monoclonal antibodies had neutralization activity. Results from IFA and western blotting showed that 12C10 was a cross-reactive antibody against both of SARS-CoV-2 and SARS-CoV. Results from conservative and structural analysis showed that 350VYAWN354 was a highly conserved epitope and exposed on the surface of SARS-CoV-2 S trimer, whereas 473YQAGSTP479 located in the receptor binding motif (RBM) was variable among different SARS-CoV-2 strains. 407VRQIAP412 was a highly conserved, but cryptic epitope shared between SARS-CoV-2 and SARS-CoV. These findings provide important information for understanding the humoral antibody response to the RBD of SARS-CoV-2 S protein and may facilitate further efforts to design SARS-CoV-2 vaccines and the target of COVID-19 diagnostic.


Subject(s)
B-Lymphocytes/immunology , Epitopes, B-Lymphocyte/metabolism , Peptides/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Motifs/genetics , Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , Antibodies, Viral/metabolism , COVID-19 Vaccines , Conserved Sequence/genetics , Epitope Mapping , Epitopes, B-Lymphocyte/genetics , HEK293 Cells , Humans , Immunity, Humoral , Peptides/genetics , Protein Binding , Spike Glycoprotein, Coronavirus/genetics
7.
Front Immunol ; 12: 714177, 2021.
Article in English | MEDLINE | ID: covidwho-1444042

ABSTRACT

Sepsis continues to be a major cause of morbidity, mortality, and post-recovery disability in patients with a wide range of non-infectious and infectious inflammatory disorders, including COVID-19. The clinical onset of sepsis is often marked by the explosive release into the extracellular fluids of a multiplicity of host-derived cytokines and other pro-inflammatory hormone-like messengers from endogenous sources ("cytokine storm"). In patients with sepsis, therapies to counter the pro-inflammatory torrent, even when administered early, typically fall short. The major focus of our proposed essay is to promote pre-clinical studies with hCG (human chorionic gonadotropin) as a potential anti-inflammatory therapy for sepsis.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Chorionic Gonadotropin/therapeutic use , Peptides/therapeutic use , Sepsis/drug therapy , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/metabolism , Bacteria/metabolism , Chorionic Gonadotropin/chemistry , Chorionic Gonadotropin/metabolism , Cytokine Release Syndrome/drug therapy , Glycoproteins/chemistry , Glycoproteins/metabolism , Humans , Inflammation , Peptides/chemistry , Peptides/metabolism
8.
J Med Chem ; 64(19): 14887-14894, 2021 10 14.
Article in English | MEDLINE | ID: covidwho-1428719

ABSTRACT

Antiviral treatments of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been extensively pursued to conquer the pandemic. To inhibit the viral entry to the host cell, we designed and obtained three peptide sequences via quartz crystal microbalance measurement screening, which showed high affinity at nanomole to the S1 subunit of the spike protein and wild-type SARS-CoV-2 pseudovirus. Circular dichroism spectroscopy measurements revealed significant conformation changes of the S1 protein upon encounter with the three peptides. The peptides were able to effectively block the infection of a pseudovirus to 50% by inhibiting the host cell lines binding with the S1 protein, evidenced by the results from Western blotting and pseudovirus luciferase assay. Moreover, the combination of the three peptides could increase the inhibitory rate to 75%. In conclusion, the three chemically synthetic neutralizing peptides and their combinations hold promising potential as effective therapeutics in the prevention and treatment of COVID-19.


Subject(s)
Peptides/metabolism , Spike Glycoprotein, Coronavirus/metabolism , A549 Cells , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/pathology , COVID-19/virology , Cell Survival/drug effects , Circular Dichroism , Humans , Neutralization Tests , Peptides/chemistry , Peptides/pharmacology , Protein Binding , Protein Subunits/chemistry , Protein Subunits/metabolism , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/chemistry , Virus Internalization/drug effects
9.
J Phys Chem Lett ; 12(16): 4059-4066, 2021 Apr 29.
Article in English | MEDLINE | ID: covidwho-1387120

ABSTRACT

The spike glycoprotein (S-protein) mediates SARS-CoV-2 entry via intermolecular interaction with human angiotensin-converting enzyme 2. The receptor binding domain (RBD) of the S-protein has been considered critical for this interaction and acts as the target of numerous neutralizing antibodies and antiviral peptides. This study used the fragment molecular orbital method to analyze the interactions between the RBD and antibodies/peptides and extracted crucial residues that can be used as epitopes. The interactions evaluated as interfragment interaction energy values between the RBD and 12 antibodies/peptides showed a fairly good correlation with the experimental activity pIC50 (R2 = 0.540). Nine residues (T415, K417, Y421, F456, A475, F486, N487, N501, and Y505) were confirmed as being crucial. Pair interaction energy decomposition analyses showed that hydrogen bonds, electrostatic interactions, and π-orbital interactions are important. Our results provide essential information for understanding SARS-CoV-2-antibody/peptide binding and may play roles in future antibody/antiviral drug design.


Subject(s)
Angiotensin-Converting Enzyme 2/immunology , Antibodies, Neutralizing/metabolism , Antibodies, Viral/metabolism , Peptides/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Binding Sites/immunology , Epitopes/immunology , Epitopes/metabolism , Humans , Hydrogen Bonding , Models, Chemical , Protein Binding , Protein Domains , Quantum Theory , SARS-CoV-2/chemistry , Static Electricity
10.
BMC Bioinformatics ; 21(Suppl 17): 484, 2020 Dec 14.
Article in English | MEDLINE | ID: covidwho-1388725

ABSTRACT

BACKGROUND: We previously introduced PCPS (Proteasome Cleavage Prediction Server), a web-based tool to predict proteasome cleavage sites using n-grams. Here, we evaluated the ability of PCPS immunoproteasome cleavage model to discriminate CD8+ T cell epitopes. RESULTS: We first assembled an epitope dataset consisting of 844 unique virus-specific CD8+ T cell epitopes and their source proteins. We then analyzed cleavage predictions by PCPS immunoproteasome cleavage model on this dataset and compared them with those provided by a related method implemented by NetChop web server. PCPS was clearly superior to NetChop in term of sensitivity (0.89 vs. 0.79) but somewhat inferior with regard to specificity (0.55 vs. 0.60). Judging by the Mathew's Correlation Coefficient, PCPS predictions were overall superior to those provided by NetChop (0.46 vs. 0.39). We next analyzed the power of C-terminal cleavage predictions provided by the same PCPS model to discriminate CD8+ T cell epitopes, finding that they could be discriminated from random peptides with an accuracy of 0.74. Following these results, we tuned the PCPS web server to predict CD8+ T cell epitopes and predicted the entire SARS-CoV-2 epitope space. CONCLUSIONS: We report an improved version of PCPS named iPCPS for predicting proteasome cleavage sites and peptides with CD8+ T cell epitope features. iPCPS is available for free public use at https://imed.med.ucm.es/Tools/pcps/ .


Subject(s)
Epitopes, T-Lymphocyte , Proteasome Endopeptidase Complex/metabolism , Proteomics/methods , SARS-CoV-2 , Viral Proteins , COVID-19/virology , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/metabolism , Humans , Peptides/chemistry , Peptides/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/metabolism , Software , Viral Proteins/chemistry , Viral Proteins/metabolism
11.
J Proteome Res ; 19(11): 4398-4406, 2020 11 06.
Article in English | MEDLINE | ID: covidwho-1387124

ABSTRACT

Presentation of antigenic peptides by MHCI is central to cellular immune responses against viral pathogens. While adaptive immune responses versus SARS-CoV-2 can be of critical importance to both recovery and vaccine efficacy, how protein antigens from this pathogen are processed to generate antigenic peptides is largely unknown. Here, we analyzed the proteolytic processing of overlapping precursor peptides spanning the entire sequence of the S1 spike glycoprotein of SARS-CoV-2, by three key enzymes that generate antigenic peptides, aminopeptidases ERAP1, ERAP2, and IRAP. All enzymes generated shorter peptides with sequences suitable for binding onto HLA alleles, but with distinct specificity fingerprints. ERAP1 was the most efficient in generating peptides 8-11 residues long, the optimal length for HLA binding, while IRAP was the least efficient. The combination of ERAP1 with ERAP2 greatly limited the variability of peptide sequences produced. Less than 7% of computationally predicted epitopes were found to be produced experimentally, suggesting that aminopeptidase processing may constitute a significant filter to epitope presentation. These experimentally generated putative epitopes could be prioritized for SARS-CoV-2 immunogenicity studies and vaccine design. We furthermore propose that this in vitro trimming approach could constitute a general filtering method to enhance the prediction robustness for viral antigenic epitopes.


Subject(s)
Aminopeptidases/metabolism , Antigens, Viral , Epitopes , Spike Glycoprotein, Coronavirus , Antigens, Viral/chemistry , Antigens, Viral/metabolism , Chromatography, Liquid , Epitopes/chemistry , Epitopes/metabolism , HEK293 Cells , HLA Antigens/chemistry , HLA Antigens/metabolism , Humans , Peptides/analysis , Peptides/chemistry , Peptides/metabolism , Proteomics/methods , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Tandem Mass Spectrometry
12.
J Phys Chem B ; 124(44): 9785-9792, 2020 11 05.
Article in English | MEDLINE | ID: covidwho-1387110

ABSTRACT

Over 50 peptides, which were known to inhibit SARS-CoV-1, were computationally screened against the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2. Based on the binding affinity and interaction, 15 peptides were selected, which showed higher affinity compared to the α-helix of the human ACE2 receptor. Molecular dynamics simulation demonstrated that two peptides, S2P25 and S2P26, were the most promising candidates, which could potentially block the entry of SARS-CoV-2. Tyr489 and Tyr505 residues present in the "finger-like" projections of the RBD were found to be critical for peptide interaction. Hydrogen bonding and hydrophobic interactions played important roles in prompting peptide-protein binding and interaction. Structure-activity relationship indicated that peptides containing aromatic (Tyr and Phe), nonpolar (Pro, Gly, Leu, and Ala), and polar (Asn, Gln, and Cys) residues were the most significant contributors. These findings can facilitate the rational design of selective peptide inhibitors targeting the spike protein of SARS-CoV-2.


Subject(s)
Antiviral Agents/metabolism , Betacoronavirus/chemistry , Peptides/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Antiviral Agents/chemistry , Binding Sites , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Molecular Docking Simulation , Molecular Dynamics Simulation , Molecular Structure , Peptides/chemistry , Protein Binding , Protein Domains , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Structure-Activity Relationship
13.
J Chem Inf Model ; 60(12): 5815-5831, 2020 12 28.
Article in English | MEDLINE | ID: covidwho-1387107

ABSTRACT

Herein, we investigate the structure and flexibility of the hydrated SARS-CoV-2 main protease by means of 2.0 µs molecular dynamics (MD) simulations in explicit solvent. After having performed electrostatic pKa calculations on several X-ray structures, we consider both the native (unbound) configuration of the enzyme and its noncovalent complex with a model peptide, Ace-Ala-Val-Leu-Gln∼Ser-Nme, which mimics the polyprotein sequence recognized at the active site. For each configuration, we also study their monomeric and homodimeric forms. The simulations of the unbound systems show that the relative orientation of domain III is not stable in the monomeric form and provide further details about interdomain motions, protomer-protomer interactions, inter-residue contacts, accessibility at the catalytic site, etc. In the presence of the peptide substrate, the monomeric protease exhibits a stable interdomain arrangement, but the relative orientation between the scissile peptide bond and the catalytic dyad is not favorable for catalysis. By means of comparative analysis, we further assess the catalytic impact of the enzyme dimerization, the actual flexibility of the active site region, and other structural effects induced by substrate binding. Overall, our computational results complement previous crystallographic studies on the SARS-CoV-2 enzyme and, together with other simulation studies, should contribute to outline useful structure-activity relationships.


Subject(s)
COVID-19/metabolism , Coronavirus 3C Proteases/metabolism , Peptides/chemistry , Peptides/metabolism , SARS-CoV-2/metabolism , Amino Acid Sequence , Catalytic Domain , Dimerization , Humans , Molecular Dynamics Simulation , Protein Conformation , Static Electricity , Structure-Activity Relationship , Substrate Specificity , Thermodynamics
14.
Int J Mol Sci ; 22(17)2021 Aug 30.
Article in English | MEDLINE | ID: covidwho-1379977

ABSTRACT

A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been identified as the pathogen responsible for the outbreak of a severe, rapidly developing pneumonia (Coronavirus disease 2019, COVID-19). The virus enzyme, called 3CLpro or main protease (Mpro), is essential for viral replication, making it a most promising target for antiviral drug development. Recently, we adopted the drug repurposing as appropriate strategy to give fast response to global COVID-19 epidemic, by demonstrating that the zonulin octapeptide inhibitor AT1001 (Larazotide acetate) binds Mpro catalytic domain. Thus, in the present study we tried to investigate the antiviral activity of AT1001, along with five derivatives, by cell-based assays. Our results provide with the identification of AT1001 peptide molecular framework for lead optimization step to develop new generations of antiviral agents of SARS-CoV-2 with an improved biological activity, expanding the chance for success in clinical trials.


Subject(s)
Antiviral Agents/pharmacology , Molecular Docking Simulation , Oligopeptides/chemistry , Peptides/metabolism , SARS-CoV-2/drug effects , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/therapeutic use , Binding Sites , COVID-19/drug therapy , COVID-19/virology , Catalytic Domain , Cell Line , Cytomegalovirus/drug effects , Drug Repositioning , Herpesvirus 3, Human/drug effects , Humans , Molecular Dynamics Simulation , Peptides/chemical synthesis , Peptides/pharmacology , Peptides/therapeutic use , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Viral Matrix Proteins/chemistry , Viral Matrix Proteins/metabolism
15.
Int J Mol Sci ; 22(17)2021 Aug 24.
Article in English | MEDLINE | ID: covidwho-1379976

ABSTRACT

Antisense peptide technology (APT) is based on a useful heuristic algorithm for rational peptide design. It was deduced from empirical observations that peptides consisting of complementary (sense and antisense) amino acids interact with higher probability and affinity than the randomly selected ones. This phenomenon is closely related to the structure of the standard genetic code table, and at the same time, is unrelated to the direction of its codon sequence translation. The concept of complementary peptide interaction is discussed, and its possible applications to diagnostic tests and bioengineering research are summarized. Problems and difficulties that may arise using APT are discussed, and possible solutions are proposed. The methodology was tested on the example of SARS-CoV-2. It is shown that the CABS-dock server accurately predicts the binding of antisense peptides to the SARS-CoV-2 receptor binding domain without requiring predefinition of the binding site. It is concluded that the benefits of APT outweigh the costs of random peptide screening and could lead to considerable savings in time and resources, especially if combined with other computational and immunochemical methods.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , Peptides/metabolism , Protein Engineering/methods , Spike Glycoprotein, Coronavirus/isolation & purification , Algorithms , Amino Acid Sequence/genetics , Binding Sites/genetics , COVID-19/blood , COVID-19/virology , Humans , Immunochemistry/methods , Molecular Docking Simulation , Peptides/genetics , Protein Binding/genetics , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/metabolism
16.
Bioorg Med Chem Lett ; 50: 128333, 2021 10 15.
Article in English | MEDLINE | ID: covidwho-1363893

ABSTRACT

Specific anti-coronaviral drugs complementing available vaccines are urgently needed to fight the COVID-19 pandemic. Given its high conservation across the betacoronavirus genus and dissimilarity to human proteases, the SARS-CoV-2 main protease (Mpro) is an attractive drug target. SARS-CoV-2 Mpro inhibitors have been developed at unprecedented speed, most of them being substrate-derived peptidomimetics with cysteine-modifying warheads. In this study, Mpro has proven resistant towards the identification of high-affinity short substrate-derived peptides and peptidomimetics without warheads. 20 cyclic and linear substrate analogues bearing natural and unnatural residues, which were predicted by computational modelling to bind with high affinity and designed to establish structure-activity relationships, displayed no inhibitory activity at concentrations as high as 100 µM. Only a long linear peptide covering residues P6 to P5' displayed moderate inhibition (Ki = 57 µM). Our detailed findings will inform current and future drug discovery campaigns targeting Mpro.


Subject(s)
COVID-19/pathology , Coronavirus 3C Proteases/antagonists & inhibitors , Protease Inhibitors/chemistry , SARS-CoV-2/enzymology , COVID-19/virology , Coronavirus 3C Proteases/metabolism , Cysteine/chemistry , Cysteine/metabolism , Humans , Lactams/chemistry , Lactams/metabolism , Leucine/chemistry , Leucine/metabolism , Nitriles/chemistry , Nitriles/metabolism , Peptides/chemistry , Peptides/metabolism , Peptidomimetics/chemistry , Peptidomimetics/metabolism , Proline/chemistry , Proline/metabolism , Protease Inhibitors/metabolism , SARS-CoV-2/isolation & purification , Structure-Activity Relationship , Substrate Specificity
17.
Molecules ; 26(16)2021 Aug 12.
Article in English | MEDLINE | ID: covidwho-1355016

ABSTRACT

The COVID-19 outbreak has rapidly spread on a global scale, affecting the economy and public health systems throughout the world. In recent years, peptide-based therapeutics have been widely studied and developed to treat infectious diseases, including viral infections. Herein, the antiviral effects of the lysine linked dimer des-Cys11, Lys12,Lys13-(pBthTX-I)2K ((pBthTX-I)2K)) and derivatives against SARS-CoV-2 are reported. The lead peptide (pBthTX-I)2K and derivatives showed attractive inhibitory activities against SARS-CoV-2 (EC50 = 28-65 µM) and mostly low cytotoxic effect (CC50 > 100 µM). To shed light on the mechanism of action underlying the peptides' antiviral activity, the Main Protease (Mpro) and Papain-Like protease (PLpro) inhibitory activities of the peptides were assessed. The synthetic peptides showed PLpro inhibition potencies (IC50s = 1.0-3.5 µM) and binding affinities (Kd = 0.9-7 µM) at the low micromolar range but poor inhibitory activity against Mpro (IC50 > 10 µM). The modeled binding mode of a representative peptide of the series indicated that the compound blocked the entry of the PLpro substrate toward the protease catalytic cleft. Our findings indicated that non-toxic dimeric peptides derived from the Bothropstoxin-I have attractive cellular and enzymatic inhibitory activities, thereby suggesting that they are promising prototypes for the discovery and development of new drugs against SARS-CoV-2 infection.


Subject(s)
Crotalid Venoms/chemistry , Dimerization , Papain/antagonists & inhibitors , Peptides/chemistry , Peptides/pharmacology , SARS-CoV-2/enzymology , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Molecular Docking Simulation , Papain/chemistry , Papain/metabolism , Peptides/metabolism , Protease Inhibitors/chemistry , Protease Inhibitors/metabolism , Protease Inhibitors/pharmacology , Protein Conformation , SARS-CoV-2/drug effects
18.
Brief Bioinform ; 22(2): 936-945, 2021 03 22.
Article in English | MEDLINE | ID: covidwho-1352108

ABSTRACT

Interleukin 6 (IL-6) is a pro-inflammatory cytokine that stimulates acute phase responses, hematopoiesis and specific immune reactions. Recently, it was found that the IL-6 plays a vital role in the progression of COVID-19, which is responsible for the high mortality rate. In order to facilitate the scientific community to fight against COVID-19, we have developed a method for predicting IL-6 inducing peptides/epitopes. The models were trained and tested on experimentally validated 365 IL-6 inducing and 2991 non-inducing peptides extracted from the immune epitope database. Initially, 9149 features of each peptide were computed using Pfeature, which were reduced to 186 features using the SVC-L1 technique. These features were ranked based on their classification ability, and the top 10 features were used for developing prediction models. A wide range of machine learning techniques has been deployed to develop models. Random Forest-based model achieves a maximum AUROC of 0.84 and 0.83 on training and independent validation dataset, respectively. We have also identified IL-6 inducing peptides in different proteins of SARS-CoV-2, using our best models to design vaccine against COVID-19. A web server named as IL-6Pred and a standalone package has been developed for predicting, designing and screening of IL-6 inducing peptides (https://webs.iiitd.edu.in/raghava/il6pred/).


Subject(s)
COVID-19/physiopathology , Computer Simulation , Interleukin-6/biosynthesis , Peptides/metabolism , COVID-19/virology , Databases, Protein , Datasets as Topic , Humans , Interleukin-6/physiology , Machine Learning , SARS-CoV-2/isolation & purification
19.
Commun Biol ; 4(1): 366, 2021 03 19.
Article in English | MEDLINE | ID: covidwho-1351981

ABSTRACT

GFP fusion-based fluorescence-detection size-exclusion chromatography (FSEC) has been widely employed for membrane protein expression screening. However, fused GFP itself may occasionally affect the expression and/or stability of the targeted membrane protein, leading to both false-positive and false-negative results in expression screening. Furthermore, GFP fusion technology is not well suited for some membrane proteins, depending on their membrane topology. Here, we developed an FSEC assay utilizing nanobody (Nb) technology, named FSEC-Nb, in which targeted membrane proteins are fused to a small peptide tag and recombinantly expressed. The whole-cell extracts are solubilized, mixed with anti-peptide Nb fused to GFP for FSEC analysis. FSEC-Nb enables the evaluation of the expression, monodispersity and thermostability of membrane proteins without the need for purification but does not require direct GFP fusion to targeted proteins. Our results show FSEC-Nb as a powerful tool for expression screening of membrane proteins for structural and functional studies.


Subject(s)
Chromatography, Gel , Green Fluorescent Proteins/metabolism , Membrane Proteins/metabolism , Nanotechnology , Peptides/metabolism , Single-Domain Antibodies/immunology , Animals , Cryoelectron Microscopy , Cysteine Loop Ligand-Gated Ion Channel Receptors/genetics , Cysteine Loop Ligand-Gated Ion Channel Receptors/immunology , Cysteine Loop Ligand-Gated Ion Channel Receptors/metabolism , Fish Proteins/genetics , Fish Proteins/immunology , Fish Proteins/metabolism , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/immunology , HEK293 Cells , Humans , Membrane Proteins/genetics , Membrane Proteins/immunology , Oryzias/genetics , Oryzias/metabolism , Peptides/genetics , Peptides/immunology , Protein Stability , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/immunology , Recombinant Fusion Proteins/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Spectrometry, Fluorescence , Temperature , Viral Proteins/genetics , Viral Proteins/immunology , Viral Proteins/metabolism
20.
J Am Chem Soc ; 143(33): 13205-13211, 2021 08 25.
Article in English | MEDLINE | ID: covidwho-1349637

ABSTRACT

The receptor binding and proteolysis of Spike of SARS-CoV-2 release its S2 subunit to rearrange and catalyze viral-cell fusion. This deploys the fusion peptide for insertion into the cell membranes targeted. We show that this fusion peptide transforms from intrinsic disorder in solution into a wedge-shaped structure inserted in bilayered micelles, according to chemical shifts, 15N NMR relaxation, and NOEs. The globular fold of three helices contrasts the open, extended forms of this region observed in the electron density of compact prefusion states. In the hydrophobic, narrow end of the wedge, helices 1 and 2 contact the fatty acyl chains of phospholipids, according to NOEs and proximity to a nitroxide spin label deep in the membrane mimic. The polar end of the wedge may engage and displace lipid head groups and bind Ca2+ ions for membrane fusion. Polar helix 3 protrudes from the bilayer where it might be accessible to antibodies.


Subject(s)
Micelles , Peptides/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , COVID-19/pathology , COVID-19/virology , Humans , Hydrophobic and Hydrophilic Interactions , Peptides/chemistry , Phospholipids/chemistry , Phospholipids/metabolism , Protein Binding , Protein Conformation, alpha-Helical , Protein Subunits/chemistry , Protein Subunits/metabolism , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...