Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 643
Filter
Add filters

Document Type
Year range
1.
PLoS Comput Biol ; 17(12): e1009675, 2021 12.
Article in English | MEDLINE | ID: covidwho-1619980

ABSTRACT

Identifying the epitope of an antibody is a key step in understanding its function and its potential as a therapeutic. Sequence-based clonal clustering can identify antibodies with similar epitope complementarity, however, antibodies from markedly different lineages but with similar structures can engage the same epitope. We describe a novel computational method for epitope profiling based on structural modelling and clustering. Using the method, we demonstrate that sequence dissimilar but functionally similar antibodies can be found across the Coronavirus Antibody Database, with high accuracy (92% of antibodies in multiple-occupancy structural clusters bind to consistent domains). Our approach functionally links antibodies with distinct genetic lineages, species origins, and coronavirus specificities. This indicates greater convergence exists in the immune responses to coronaviruses than is suggested by sequence-based approaches. Our results show that applying structural analytics to large class-specific antibody databases will enable high confidence structure-function relationships to be drawn, yielding new opportunities to identify functional convergence hitherto missed by sequence-only analysis.


Subject(s)
Antigens, Viral/chemistry , COVID-19/immunology , COVID-19/virology , Epitopes, B-Lymphocyte/chemistry , SARS-CoV-2/chemistry , SARS-CoV-2/immunology , Amino Acid Sequence , Animals , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/genetics , Antibodies, Viral/chemistry , Antibodies, Viral/genetics , Antibodies, Viral/metabolism , Antibody Specificity , Antigen-Antibody Complex/chemistry , Antigen-Antibody Complex/genetics , Antigen-Antibody Reactions/genetics , Antigen-Antibody Reactions/immunology , Computational Biology , Coronavirus/chemistry , Coronavirus/genetics , Coronavirus/immunology , Databases, Chemical , Epitope Mapping , Epitopes, B-Lymphocyte/genetics , Humans , Mice , Models, Molecular , Pandemics , SARS-CoV-2/genetics , Single-Domain Antibodies/immunology
2.
J Virol ; 94(13)2020 06 16.
Article in English | MEDLINE | ID: covidwho-1583223

ABSTRACT

Fusion with, and subsequent entry into, the host cell is one of the critical steps in the life cycle of enveloped viruses. For Middle East respiratory syndrome coronavirus (MERS-CoV), the spike (S) protein is the main determinant of viral entry. Proteolytic cleavage of the S protein exposes its fusion peptide (FP), which initiates the process of membrane fusion. Previous studies on the related severe acute respiratory syndrome coronavirus (SARS-CoV) FP have shown that calcium ions (Ca2+) play an important role in fusogenic activity via a Ca2+ binding pocket with conserved glutamic acid (E) and aspartic acid (D) residues. SARS-CoV and MERS-CoV FPs share a high sequence homology, and here, we investigated whether Ca2+ is required for MERS-CoV fusion by screening a mutant array in which E and D residues in the MERS-CoV FP were substituted with neutrally charged alanines (A). Upon verifying mutant cell surface expression and proteolytic cleavage, we tested their ability to mediate pseudoparticle (PP) infection of host cells in modulating Ca2+ environments. Our results demonstrate that intracellular Ca2+ enhances MERS-CoV wild-type (WT) PP infection by approximately 2-fold and that E891 is a crucial residue for Ca2+ interaction. Subsequent electron spin resonance (ESR) experiments revealed that this enhancement could be attributed to Ca2+ increasing MERS-CoV FP fusion-relevant membrane ordering. Intriguingly, isothermal calorimetry showed an approximate 1:1 MERS-CoV FP to Ca2+ ratio, as opposed to an 1:2 SARS-CoV FP to Ca2+ ratio, suggesting significant differences in FP Ca2+ interactions of MERS-CoV and SARS-CoV FP despite their high sequence similarity.IMPORTANCE Middle East respiratory syndrome coronavirus (MERS-CoV) is a major emerging infectious disease with zoonotic potential and has reservoirs in dromedary camels and bats. Since its first outbreak in 2012, the virus has repeatedly transmitted from camels to humans, with 2,468 confirmed cases causing 851 deaths. To date, there are no efficacious drugs and vaccines against MERS-CoV, increasing its potential to cause a public health emergency. In order to develop novel drugs and vaccines, it is important to understand the molecular mechanisms that enable the virus to infect host cells. Our data have found that calcium is an important regulator of viral fusion by interacting with negatively charged residues in the MERS-CoV FP region. This information can guide therapeutic solutions to block this calcium interaction and also repurpose already approved drugs for this use for a fast response to MERS-CoV outbreaks.


Subject(s)
Calcium/metabolism , Coronavirus Infections/metabolism , Coronavirus Infections/virology , Host-Pathogen Interactions , Ions/metabolism , Membrane Fusion , Middle East Respiratory Syndrome Coronavirus/physiology , Virus Internalization , Amino Acid Sequence , Amino Acid Substitution , Animals , Cell Line , Chlorocebus aethiops , Humans , Middle East Respiratory Syndrome Coronavirus/pathogenicity , Models, Molecular , Mutation , Protein Binding , Proteolysis , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Structure-Activity Relationship , Vero Cells , Virulence , Virus Assembly
3.
Science ; 372(6547): 1169-1175, 2021 06 11.
Article in English | MEDLINE | ID: covidwho-1583231

ABSTRACT

Emergent resistance to all clinical antibiotics calls for the next generation of therapeutics. Here we report an effective antimicrobial strategy targeting the bacterial hydrogen sulfide (H2S)-mediated defense system. We identified cystathionine γ-lyase (CSE) as the primary generator of H2S in two major human pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, and discovered small molecules that inhibit bacterial CSE. These inhibitors potentiate bactericidal antibiotics against both pathogens in vitro and in mouse models of infection. CSE inhibitors also suppress bacterial tolerance, disrupting biofilm formation and substantially reducing the number of persister bacteria that survive antibiotic treatment. Our results establish bacterial H2S as a multifunctional defense factor and CSE as a drug target for versatile antibiotic enhancers.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cystathionine gamma-Lyase/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Hydrogen Sulfide/metabolism , Pseudomonas aeruginosa/drug effects , Staphylococcus aureus/drug effects , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/metabolism , Biofilms , Crystallography, X-Ray , Cystathionine gamma-Lyase/chemistry , Cystathionine gamma-Lyase/genetics , Cystathionine gamma-Lyase/metabolism , Drug Discovery , Drug Resistance, Bacterial , Drug Synergism , Drug Tolerance , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/metabolism , Mice , Microbial Sensitivity Tests , Models, Molecular , Molecular Docking Simulation , Molecular Structure , Pseudomonas Infections/drug therapy , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/enzymology , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/growth & development , Small Molecule Libraries/chemistry , Small Molecule Libraries/metabolism , Small Molecule Libraries/pharmacology , Staphylococcal Infections/drug therapy , Staphylococcal Infections/microbiology , Staphylococcus aureus/enzymology , Staphylococcus aureus/genetics , Staphylococcus aureus/growth & development
4.
Molecules ; 27(1)2022 Jan 01.
Article in English | MEDLINE | ID: covidwho-1580563

ABSTRACT

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.


Subject(s)
Angiotensin-Converting Enzyme 2 , Bromelains , Computer Simulation , Protein Interaction Domains and Motifs , SARS-CoV-2 , Angiotensin-Converting Enzyme 2/chemistry , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Bromelains/chemistry , Bromelains/pharmacology , COVID-19/drug therapy , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Peptides/chemistry , Peptides/pharmacology , Protein Binding , SARS-CoV-2/chemistry , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/chemistry
5.
J Med Chem ; 64(8): 4991-5000, 2021 04 22.
Article in English | MEDLINE | ID: covidwho-1574766

ABSTRACT

The main protease (3CL Mpro) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, is an essential enzyme for viral replication with no human counterpart, making it an attractive drug target. To date, no small-molecule clinical drugs are available that specifically inhibit SARS-CoV-2 Mpro. To aid rational drug design, we determined a neutron structure of Mpro in complex with the α-ketoamide inhibitor telaprevir at near-physiological (22 °C) temperature. We directly observed protonation states in the inhibitor complex and compared them with those in the ligand-free Mpro, revealing modulation of the active-site protonation states upon telaprevir binding. We suggest that binding of other α-ketoamide covalent inhibitors can lead to the same protonation state changes in the Mpro active site. Thus, by studying the protonation state changes induced by inhibitors, we provide crucial insights to help guide rational drug design, allowing precise tailoring of inhibitors to manipulate the electrostatic environment of SARS-CoV-2 Mpro.


Subject(s)
Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/chemistry , Oligopeptides/chemistry , Binding Sites , Coronavirus 3C Proteases/metabolism , Crystallography/methods , Crystallography, X-Ray , Cysteine Proteinase Inhibitors/chemistry , Cysteine Proteinase Inhibitors/metabolism , Models, Molecular , Neutrons , Oligopeptides/metabolism , Protein Conformation , Protons
6.
Mol Immunol ; 141: 287-296, 2022 01.
Article in English | MEDLINE | ID: covidwho-1559780

ABSTRACT

As the second wave of COVID-19 launched, various variants of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) have emerged with a dramatic global spread amongst millions of people causing unprecedented case fatalities and economic shut-downs. That initiated a necessity for developing specific diagnostics and therapeutics along with vaccines to control such a pandemic. This endeavor describes generation of murine derived recombinant single-chain fragment variable (scFv) as a monoclonal antibody (MAb) platform targeting the receptor binding domain (RBD) of Spike protein of SARS-CoV-2. A specific synthesized RBD coding sequence was cloned and expressed in Baculovirus expression system. The recombinant RBD (rRBD) was ascertained to be at the proper encoding size of ∼ 600bp and expressed protein of the molecular weight of ∼ 21KDa. Purified rRBD was proved genuinely antigenic and immunogenic, exhibiting specific reactivity to anti-SARS-CoV-2 antibody in an indirect enzyme-linked immunosorbent assay (ELISA), and inducing strong seroconversion in immunized mice. The scFv phage display library against rRBD was successfully constructed, revealing ∼ 90 % recombination frequency, and great enriching factor reaching 88 % and 25 % in polyclonal Ab-based and MAb-based ELISAs, respectively. Typically, three unique scFvs were generated, selected, purified and molecularly identified. That was manifested by their: accurate structure, close relation to the mouse immunoglobulin (Ig) superfamily, right anchored six complementarily-determining regions (CDRs) as three within variable heavy (vH) and variable light (vL) regions each, and proper configuration of the three-dimensional (3D) structure. Besides, their expression downstream in a non-suppressive amber codon of E. coli strain SS32 created a distinct protein band at an apparent molecular weight of ∼ 27KDa. Moreover, the purified scFvs showed authentic immunoreactivity and specificity to both rRBD and SARS-CoV-2 in western blot and ELISA. Accordingly, these developed scFvs platform might be a functional candidate for research, inexpensive diagnostics and therapeutics, mitigating spread of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , COVID-19 Serological Testing , COVID-19/diagnosis , Cell Surface Display Techniques , Epitopes/immunology , Receptors, Virus/metabolism , SARS-CoV-2/immunology , Single-Chain Antibodies/immunology , Spike Glycoprotein, Coronavirus/immunology , Amino Acid Sequence , Animals , Antibodies, Monoclonal/biosynthesis , Antibodies, Viral/blood , Antibody Specificity , Baculoviridae , COVID-19/prevention & control , Escherichia coli , Female , Genetic Vectors , Mice , Mice, Inbred BALB C , Models, Molecular , Peptide Library , Protein Conformation , Protein Domains , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/immunology , Sequence Alignment , Sequence Homology, Amino Acid , Single-Chain Antibodies/biosynthesis , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
7.
PLoS One ; 16(11): e0258645, 2021.
Article in English | MEDLINE | ID: covidwho-1518355

ABSTRACT

All approved coronavirus disease 2019 (COVID-19) vaccines in current use are safe, effective, and reduce the risk of severe illness. Although data on the immunological presentation of patients with COVID-19 is limited, increasing experimental evidence supports the significant contribution of B and T cells towards the resolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Despite the availability of several COVID-19 vaccines with high efficacy, more effective vaccines are still needed to protect against the new variants of SARS-CoV-2. Employing a comprehensive immunoinformatic prediction algorithm and leveraging the genetic closeness with SARS-CoV, we have predicted potential immune epitopes in the structural proteins of SARS-CoV-2. The S and N proteins of SARS-CoV-2 and SARS-CoVs are main targets of antibody detection and have motivated us to design four multi-epitope vaccines which were based on our predicted B- and T-cell epitopes of SARS-CoV-2 structural proteins. The cardinal epitopes selected for the vaccine constructs are predicted to possess antigenic, non-allergenic, and cytokine-inducing properties. Additionally, some of the predicted epitopes have been experimentally validated in published papers. Furthermore, we used the C-ImmSim server to predict effective immune responses induced by the epitope-based vaccines. Taken together, the immune epitopes predicted in this study provide a platform for future experimental validations which may facilitate the development of effective vaccine candidates and epitope-based serological diagnostic assays.


Subject(s)
Computational Biology , Epitope Mapping , SARS-CoV-2/immunology , Viral Structural Proteins/immunology , Amino Acid Sequence , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Databases as Topic , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/immunology , Histocompatibility Antigens Class I/metabolism , Humans , Models, Molecular , Protein Conformation , Reproducibility of Results , Viral Structural Proteins/chemistry
8.
Sci Rep ; 11(1): 22042, 2021 11 11.
Article in English | MEDLINE | ID: covidwho-1510622

ABSTRACT

The mutation of SARS-CoV-2 influences viral function as residue replacements affect both physiochemical properties and folding conformations. Although a large amount of data on SARS-CoV-2 is available, the investigation of how viral functions change in response to mutations is hampered by a lack of effective structural analysis. Here, we exploit the advances of protein structure fingerprint technology to study the folding conformational changes induced by mutations. With integration of both protein sequences and folding conformations, the structures are aligned for SARS-CoV to SARS-CoV-2, including Alpha variant (lineage B.1.1.7) and Delta variant (lineage B.1.617.2). The results showed that the virus evolution with change in mutational positions and physicochemical properties increased the affinity between spike protein and ACE2, which plays a critical role in coronavirus entry into human cells. Additionally, these structural variations impact vaccine effectiveness and drug function over the course of SARS-CoV-2 evolution. The analysis of structural variations revealed how the coronavirus has gradually evolved in both structure and function and how the SARS-CoV-2 variants have contributed to more severe acute disease worldwide.


Subject(s)
COVID-19/virology , Evolution, Molecular , Mutation , SARS-CoV-2/genetics , Amino Acid Sequence , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , Humans , Models, Molecular , Protein Conformation , Protein Folding , Protein Interaction Maps , Protein Multimerization , SARS Virus/chemistry , SARS Virus/genetics , SARS Virus/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/metabolism , Sequence Alignment , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
9.
J Phys Chem Lett ; 12(45): 11199-11205, 2021 Nov 18.
Article in English | MEDLINE | ID: covidwho-1510547

ABSTRACT

Recent advances in RNA-based medicine have provided new opportunities for the global current challenge, i.e., the COVID-19 pandemic. Novel vaccines are based on a messenger RNA (mRNA) motif with a lipid nanoparticle (LNP) vector, consisting of high content of unique pH-sensitive ionizable lipids (ILs). Here we provide molecular insights into the role of the ILs and lipid mixtures used in current mRNA vaccines. We observed that the lipid mixtures adopted a nonlamellar organization, with ILs separating into a very disordered, pH-sensitive phase. We describe structural differences of the two ILs leading to their different congregation, with implications for the vaccine stability. Finally, as RNA interacts preferentially with IL-rich phases located at the regions with high curvature of lipid phase, local changes in RNA flexibility and base pairing are induced by lipids. A proper atomistic understanding of RNA-lipid interactions may enable rational tailoring of LNP composition for efficient RNA delivery.


Subject(s)
COVID-19 Vaccines/chemistry , Lipids/chemistry , RNA, Messenger/chemistry , Humans , Lipid Bilayers/chemistry , Models, Molecular , Molecular Dynamics Simulation
10.
Nat Commun ; 12(1): 6343, 2021 11 03.
Article in English | MEDLINE | ID: covidwho-1500461

ABSTRACT

Peptide secondary metabolites are common in nature and have diverse pharmacologically-relevant functions, from antibiotics to cross-kingdom signaling. Here, we present a method to design large libraries of modified peptides in Escherichia coli and screen them in vivo to identify those that bind to a single target-of-interest. Constrained peptide scaffolds were produced using modified enzymes gleaned from microbial RiPP (ribosomally synthesized and post-translationally modified peptide) pathways and diversified to build large libraries. The binding of a RiPP to a protein target leads to the intein-catalyzed release of an RNA polymerase σ factor, which drives the expression of selectable markers. As a proof-of-concept, a selection was performed for binding to the SARS-CoV-2 Spike receptor binding domain. A 1625 Da constrained peptide (AMK-1057) was found that binds with similar affinity (990 ± 5 nM) as an ACE2-derived peptide. This demonstrates a generalizable method to identify constrained peptides that adhere to a single protein target, as a step towards "molecular glues" for therapeutics and diagnostics.


Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Peptides/chemistry , Peptides/pharmacology , SARS-CoV-2/drug effects , COVID-19/drug therapy , COVID-19/virology , Drug Design , Drug Evaluation, Preclinical , Humans , Kinetics , Models, Molecular , Peptides/genetics , Protein Binding , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
11.
Commun Biol ; 4(1): 1240, 2021 10 29.
Article in English | MEDLINE | ID: covidwho-1493232

ABSTRACT

Circular tandem repeat proteins ('cTRPs') are de novo designed protein scaffolds (in this and prior studies, based on antiparallel two-helix bundles) that contain repeated protein sequences and structural motifs and form closed circular structures. They can display significant stability and solubility, a wide range of sizes, and are useful as protein display particles for biotechnology applications. However, cTRPs also demonstrate inefficient self-assembly from smaller subunits. In this study, we describe a new generation of cTRPs, with longer repeats and increased interaction surfaces, which enhanced the self-assembly of two significantly different sizes of homotrimeric constructs. Finally, we demonstrated functionalization of these constructs with (1) a hexameric array of peptide-binding SH2 domains, and (2) a trimeric array of anti-SARS CoV-2 VHH domains. The latter proved capable of sub-nanomolar binding affinities towards the viral receptor binding domain and potent viral neutralization function.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , Protein Engineering/methods , Proteins/chemistry , Proteins/metabolism , SARS-CoV-2/metabolism , Tandem Repeat Sequences , Amino Acid Sequence , COVID-19/virology , Computer Simulation , Crystallization , HEK293 Cells , Humans , Models, Molecular , Neutralization Tests , Protein Binding , Protein Domains , Protein Folding , Protein Structure, Secondary , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
12.
Molecules ; 26(21)2021 Oct 26.
Article in English | MEDLINE | ID: covidwho-1488675

ABSTRACT

In the last two years, nucleosides analogues, a class of well-established bioactive compounds, have been the subject of renewed interest from the scientific community thanks to their antiviral activity. The COVID-19 global pandemic, indeed, spread light on the antiviral drug Remdesivir, an adenine C-nucleoside analogue. This new attention of the medical community on Remdesivir prompts the medicinal chemists to investigate once again C-nucleosides. One of the essential building blocks to synthetize these compounds is the D-(+)-ribono-1,4-lactone, but some mechanistic aspects linked to the use of different carbohydrate protecting groups remain unclear. Here, we present our investigations on the use of benzylidene as a ribonolactone protecting group useful in the synthesis of C-purine nucleosides analogues. A detailed 1D and 2D NMR structural study of the obtained compounds under different reaction conditions is presented. In addition, a molecular modeling study at the B3LYP/6-31G* level of theory with the SM8 solvation model for CHCl3 and DMSO to support the obtained results is used. This study allows for clarifying mechanistic aspects as the side reactions and structural rearrangements liked to the use of the benzylidene protecting group.


Subject(s)
Benzylidene Compounds/chemistry , Lactones/chemistry , Nucleosides/chemical synthesis , Ribose/analogs & derivatives , Adenine/analogs & derivatives , Antiviral Agents/chemistry , COVID-19/drug therapy , COVID-19/prevention & control , Humans , Lactones/chemical synthesis , Magnetic Resonance Spectroscopy , Models, Molecular , Nucleosides/metabolism , Purine Nucleosides , Ribose/chemical synthesis , Ribose/chemistry , SARS-CoV-2/drug effects , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Stereoisomerism
13.
Int J Mol Sci ; 22(21)2021 Oct 27.
Article in English | MEDLINE | ID: covidwho-1488610

ABSTRACT

The angiotensin-converting enzyme 2 (ACE2) is the receptor used by SARS-CoV and SARS-CoV-2 coronaviruses to attach to cells via the receptor-binding domain (RBD) of their viral spike protein. Since the start of the COVID-19 pandemic, several structures of protein complexes involving ACE2 and RBD as well as monoclonal antibodies and nanobodies have become available. We have leveraged the structural data to design peptides to target the interaction between the RBD of SARS-CoV-2 and ACE2 and SARS-CoV and ACE2, as contrasting exemplar, as well as the dimerization surface of ACE2 monomers. The peptides were modelled using our original method: PiPreD that uses native elements of the interaction between the targeted protein and cognate partner(s) that are subsequently included in the designed peptides. These peptides recapitulate stretches of residues present in the native interface plus novel and highly diverse conformations surrogating key interactions at the interface. To facilitate the access to this information we have created a freely available and dedicated web-based repository, PepI-Covid19 database, providing convenient access to this wealth of information to the scientific community with the view of maximizing its potential impact in the development of novel therapeutic and diagnostic agents.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Host-Pathogen Interactions/drug effects , Peptides/pharmacology , Spike Glycoprotein, Coronavirus/metabolism , Binding Sites , Databases, Factual , Humans , Models, Molecular , Peptide Library , Peptides/chemistry , Protein Conformation , Protein Domains , Protein Engineering , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/chemistry
14.
Int J Mol Sci ; 22(21)2021 Oct 26.
Article in English | MEDLINE | ID: covidwho-1488607

ABSTRACT

Emerging evidence suggests that males are more susceptible to severe infection by the SARS-CoV-2 virus than females. A variety of mechanisms may underlie the observed gender-related disparities including differences in sex hormones. However, the precise mechanisms by which female sex hormones may provide protection against SARS-CoV-2 infectivity remains unknown. Here we report new insights into the molecular basis of the interactions between the SARS-CoV-2 spike (S) protein and the human ACE2 receptor. We further report that glycosylation of the ACE2 receptor enhances SARS-CoV-2 infectivity. Importantly, estrogens can disrupt glycan-glycan interactions and glycan-protein interactions between the human ACE2 and the SARS-CoV-2 thereby blocking its entry into cells. In a mouse model of COVID-19, estrogens reduced ACE2 glycosylation and thereby alveolar uptake of the SARS-CoV-2 spike protein. These results shed light on a putative mechanism whereby female sex hormones may provide protection from developing severe infection and could inform the development of future therapies against COVID-19.


Subject(s)
Estrogens/chemistry , Estrogens/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/physiology , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Animals , Biological Transport , COVID-19/drug therapy , COVID-19/metabolism , Disease Models, Animal , Estrogens/pharmacology , Glycosylation/drug effects , Human Umbilical Vein Endothelial Cells , Humans , Male , Mice, Inbred C57BL , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Polysaccharides/chemistry , Polysaccharides/metabolism , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Tunicamycin/pharmacology
15.
Biomed Res Int ; 2021: 9982729, 2021.
Article in English | MEDLINE | ID: covidwho-1476892

ABSTRACT

The human transmembrane protease serine 2 (TMPRSS2) protein plays an important role in prostate cancer progression. It also facilitates viral entry into target cells by proteolytically cleaving and activating the S protein of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In the current study, we used different available tools like SIFT, PolyPhen2.0, PROVEAN, SNAP2, PMut, MutPred2, I-Mutant Suite, MUpro, iStable, ConSurf, ModPred, SwissModel, PROCHECK, Verify3D, and TM-align to identify the most deleterious variants and to explore possible effects on the TMPRSS2 stability, structure, and function. The six missense variants tested were evaluated to have deleterious effects on the protein by SIFT, PolyPhen2.0, PROVEAN, SNAP2, and PMut. Additionally, V160M, G181R, R240C, P335L, G432A, and D435Y variants showed a decrease in stability by at least 2 servers; G181R, G432A, and D435Y are highly conserved and identified posttranslational modifications sites (PTMs) for proteolytic cleavage and ADP-ribosylation using ConSurf and ModPred servers. The 3D structure of TMPRSS2 native and mutants was generated using 7 meq as a template from the SwissModeller group, refined by ModRefiner, and validated using the Ramachandran plot. Hence, this paper can be advantageous to understand the association between these missense variants rs12329760, rs781089181, rs762108701, rs1185182900, rs570454392, and rs867186402 and susceptibility to SARS-CoV-2.


Subject(s)
COVID-19/genetics , Mutation, Missense , Serine Endopeptidases/chemistry , Serine Endopeptidases/genetics , Binding Sites , Computational Biology/methods , Evolution, Molecular , Genetic Predisposition to Disease , Humans , Models, Molecular , Phylogeny , Polymorphism, Single Nucleotide , Protein Conformation , Protein Stability , Serine Endopeptidases/metabolism
16.
Int J Biol Macromol ; 187: 976-987, 2021 Sep 30.
Article in English | MEDLINE | ID: covidwho-1474606

ABSTRACT

Coronavirus 3C-like protease (3CLpro) is a crucial target for treating coronavirus diseases including COVID-19. Our preliminary screening showed that Ampelopsis grossedentata extract (AGE) displayed potent SARS-CoV-2-3CLpro inhibitory activity, but the key constituents with SARS-CoV-2-3CLpro inhibitory effect and their mechanisms were unrevealed. Herein, a practical strategy via integrating bioactivity-guided fractionation and purification, mass spectrometry-based peptide profiling and time-dependent biochemical assay, was applied to identify the crucial constituents in AGE and to uncover their inhibitory mechanisms. The results demonstrated that the flavonoid-rich fractions (10-17.5 min) displayed strong SARS-CoV-2-3CLpro inhibitory activities, while the constituents in these fractions were isolated and their SARS-CoV-2-3CLpro inhibitory activities were investigated. Among all isolated flavonoids, dihydromyricetin, isodihydromyricetin and myricetin strongly inhibited SARS-CoV-2 3CLpro in a time-dependent manner. Further investigations demonstrated that myricetin could covalently bind on SARS-CoV-2 3CLpro at Cys300 and Cys44, while dihydromyricetin and isodihydromyricetin covalently bound at Cys300. Covalent docking coupling with molecular dynamics simulations showed the detailed interactions between the orthoquinone form of myricetin and two covalent binding sites (surrounding Cys300 and Cys44) of SARS-CoV-2 3CLpro. Collectively, the flavonoids in AGE strongly and time-dependently inhibit SARS-CoV-2 3CLpro, while the newly identified SARS-CoV-2 3CLpro inhibitors in AGE offer promising lead compounds for developing novel antiviral agents.


Subject(s)
3C Viral Proteases/chemistry , 3C Viral Proteases/metabolism , Ampelopsis/chemistry , Antiviral Agents/pharmacology , Flavonoids/pharmacology , SARS-CoV-2/enzymology , Antiviral Agents/chemistry , Binding Sites/drug effects , Cysteine/metabolism , Flavonoids/chemistry , Flavonols/chemistry , Flavonols/pharmacology , Mass Spectrometry , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Plant Extracts/chemistry , Plant Extracts/pharmacology , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Protein Binding/drug effects , Protein Conformation/drug effects , SARS-CoV-2/drug effects
17.
Sci Rep ; 11(1): 20383, 2021 10 14.
Article in English | MEDLINE | ID: covidwho-1469988

ABSTRACT

SARS-CoV-2 continues to infect an ever-expanding number of people, resulting in an increase in the number of deaths globally. With the emergence of new variants, there is a corresponding decrease in the currently available vaccine efficacy, highlighting the need for greater insights into the viral epitope profile for both vaccine design and assessment. In this study, three immunodominant linear B cell epitopes in the SARS-CoV-2 spike receptor-binding domain (RBD) were identified by immunoinformatics prediction, and confirmed by ELISA with sera from Macaca fascicularis vaccinated with a SARS-CoV-2 RBD subunit vaccine. Further immunoinformatics analyses of these three epitopes gave rise to a method of linear B cell epitope prediction and selection. B cell epitopes in the spike (S), membrane (M), and envelope (E) proteins were subsequently predicted and confirmed using convalescent sera from COVID-19 infected patients. Immunodominant epitopes were identified in three regions of the S2 domain, one region at the S1/S2 cleavage site and one region at the C-terminus of the M protein. Epitope mapping revealed that most of the amino acid changes found in variants of concern are located within B cell epitopes in the NTD, RBD, and S1/S2 cleavage site. This work provides insights into B cell epitopes of SARS-CoV-2 as well as immunoinformatics methods for B cell epitope prediction, which will improve and enhance SARS-CoV-2 vaccine development against emergent variants.


Subject(s)
COVID-19/immunology , Epitopes, B-Lymphocyte/immunology , Immunodominant Epitopes/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Viral Matrix Proteins/immunology , Animals , COVID-19/prevention & control , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Computational Biology , Coronavirus Envelope Proteins/chemistry , Coronavirus Envelope Proteins/immunology , Epitopes, B-Lymphocyte/chemistry , Humans , Immunoassay , Immunodominant Epitopes/chemistry , Macaca , Models, Molecular , Spike Glycoprotein, Coronavirus/chemistry , Viral Matrix Proteins/chemistry
18.
J Phys Chem Lett ; 12(42): 10277-10283, 2021 Oct 28.
Article in English | MEDLINE | ID: covidwho-1469948

ABSTRACT

Guanine quadruplex (G4) structures in the viral genome have a key role in modulating viruses' biological activity. While several DNA G4 structures have been experimentally resolved, RNA G4s are definitely less explored. We report the first calculated G4 structure of the RG-1 RNA sequence of SARS-CoV-2 genome, obtained by using a multiscale approach combining quantum and classical molecular modeling and corroborated by the excellent agreement between the corresponding calculated and experimental circular dichroism spectra. We prove the stability of the RG-1 G4 arrangement as well as its interaction with G4 ligands potentially inhibiting viral protein translation.


Subject(s)
COVID-19/genetics , G-Quadruplexes , Genome, Viral , RNA, Viral/chemistry , RNA, Viral/genetics , SARS-CoV-2/genetics , COVID-19/virology , Humans , Models, Molecular , Nucleic Acid Conformation
19.
Curr Top Med Chem ; 21(16): 1429-1438, 2021 Oct 25.
Article in English | MEDLINE | ID: covidwho-1468281

ABSTRACT

As a part of the efforts to quickly develop pharmaceutical treatments for COVID-19 through repurposing existing drugs, some researchers around the world have combined the recently released crystal structure of SARS-CoV-2 Mpro in complex with a covalently bonded inhibitor with virtual screening procedures employing molecular docking approaches. In this context, protease inhibitors (PIs) clinically available and currently used to treat infectious diseases, particularly viral ones, are relevant sources of promising drug candidates to inhibit the SARS-CoV-2 Mpro, a key viral enzyme involved in crucial events during its life cycle. In the present perspective, we summarized the published studies showing the promising use of HIV and HCV PIs as potential repurposing drugs against the SARS-CoV-2 Mpro.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus M Proteins/antagonists & inhibitors , Drug Repositioning , Protease Inhibitors/pharmacology , SARS-CoV-2/drug effects , Antiviral Agents/chemistry , Binding Sites , COVID-19/virology , Coronavirus M Proteins/chemistry , Coronavirus M Proteins/genetics , Coronavirus M Proteins/metabolism , Humans , Kinetics , Models, Molecular , Molecular Targeted Therapy , Protease Inhibitors/chemistry , Protein Binding , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Protein Interaction Domains and Motifs , Randomized Controlled Trials as Topic , SARS-CoV-2/enzymology , SARS-CoV-2/genetics , Thermodynamics
20.
J Am Chem Soc ; 143(42): 17646-17654, 2021 10 27.
Article in English | MEDLINE | ID: covidwho-1467047

ABSTRACT

The pandemic caused by SARS-CoV-2 has cost millions of lives and tremendous social/financial loss. The virus continues to evolve and mutate. In particular, the recently emerged "UK", "South Africa", and Delta variants show higher infectivity and spreading speed. Thus, the relationship between the mutations of certain amino acids and the spreading speed of the virus is a problem of great importance. In this respect, understanding the mutational mechanism is crucial for surveillance and prediction of future mutations as well as antibody/vaccine development. In this work, we used a coarse-grained model (that was used previously in predicting the importance of mutations of N501) to calculate the free energy change of various types of single-site or combined-site mutations. This was done for the UK, South Africa, and Delta mutants. We investigated the underlying mechanisms of the binding affinity changes for mutations at different spike protein domains of SARS-CoV-2 and provided the energy basis for the resistance of the E484 mutant to the antibody m396. Other potential mutation sites were also predicted. Furthermore, the in silico predictions were assessed by functional experiments. The results establish that the faster spreading of recently observed mutants is strongly correlated with the binding-affinity enhancement between virus and human receptor as well as with the reduction of the binding to the m396 antibody. Significantly, the current approach offers a way to predict new variants and to assess the effectiveness of different antibodies toward such variants.


Subject(s)
COVID-19/metabolism , COVID-19/virology , Mutation , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/genetics , Binding Sites , COVID-19/transmission , Humans , Models, Molecular , Spike Glycoprotein, Coronavirus/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...