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1.
J Med Chem ; 65(3): 2558-2570, 2022 02 10.
Article in English | MEDLINE | ID: covidwho-1655430

ABSTRACT

Safe and effective vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants are the best approach to successfully combat the COVID-19 pandemic. The receptor-binding domain (RBD) of the viral spike protein is a major target to develop candidate vaccines. α-Galactosylceramide (αGalCer), a potent invariant natural killer T cell (iNKT) agonist, was site-specifically conjugated to the N-terminus of the RBD to form an adjuvant-protein conjugate, which was anchored on the liposome surface. This is the first time that an iNKT cell agonist was conjugated to the protein antigen. Compared to the unconjugated RBD/αGalCer mixture, the αGalCer-RBD conjugate induced significantly stronger humoral and cellular responses. The conjugate vaccine also showed effective cross-neutralization to all variants of concern (B.1.1.7/alpha, B.1.351/beta, P.1/gamma, B.1.617.2/delta, and B.1.1.529/omicron). These results suggest that the self-adjuvanting αGalCer-RBD has great potential to be an effective COVID-19 vaccine candidate, and this strategy might be useful for designing various subunit vaccines.


Subject(s)
COVID-19 Vaccines/therapeutic use , COVID-19/therapy , Galactosylceramides/therapeutic use , Peptide Fragments/therapeutic use , SARS-CoV-2/immunology , Vaccines, Conjugate/therapeutic use , Adjuvants, Immunologic/chemistry , Adjuvants, Immunologic/therapeutic use , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Female , Galactosylceramides/chemistry , Galactosylceramides/immunology , Immunity, Humoral/drug effects , Immunity, Innate/drug effects , Interferon-gamma/metabolism , Liposomes/chemistry , Liposomes/immunology , Liposomes/therapeutic use , Mice, Inbred BALB C , Peptide Fragments/chemistry , Peptide Fragments/immunology , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/therapeutic use , Vaccines, Conjugate/chemistry , Vaccines, Conjugate/immunology
2.
MAbs ; 14(1): 2021601, 2022.
Article in English | MEDLINE | ID: covidwho-1625321

ABSTRACT

Coronavirus disease 2019, caused by SARS-CoV-2, remains an on-going pandemic, partly due to the emergence of variant viruses that can "break-through" the protection of the current vaccines and neutralizing antibodies (nAbs), highlighting the needs for broadly nAbs and next-generation vaccines. We report an antibody that exhibits breadth and potency in binding the receptor-binding domain (RBD) of the virus spike glycoprotein across SARS coronaviruses. Initially, a lead antibody was computationally discovered and crystallographically validated that binds to a highly conserved surface of the RBD of wild-type SARS-CoV-2. Subsequently, through experimental affinity enhancement and computational affinity maturation, it was further developed to bind the RBD of all concerning SARS-CoV-2 variants, SARS-CoV-1 and pangolin coronavirus with pico-molar binding affinities, consistently exhibited strong neutralization activity against wild-type SARS-CoV-2 and the Alpha and Delta variants. These results identify a vulnerable target site on coronaviruses for development of pan-sarbecovirus nAbs and vaccines.


Subject(s)
Antibodies, Viral/immunology , Antigens, Viral/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/genetics , Antibodies, Viral/metabolism , Antibody Affinity , Antibody Specificity , Antigen-Antibody Reactions , Antigens, Viral/chemistry , Antigens, Viral/genetics , Broadly Neutralizing Antibodies/genetics , Broadly Neutralizing Antibodies/metabolism , Crystallography, X-Ray , Epitopes/chemistry , Epitopes/immunology , Humans , Immunoglobulin Fragments/immunology , Molecular Docking Simulation , Monte Carlo Method , Neutralization Tests , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Protein Domains , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/immunology , Recombinant Fusion Proteins/metabolism , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics
3.
Anal Bioanal Chem ; 413(30): 7559-7585, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1503906

ABSTRACT

Subunit vaccines based on the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 provide one of the most promising strategies to fight the COVID-19 pandemic. The detailed characterization of the protein primary structure by mass spectrometry (MS) is mandatory, as described in ICHQ6B guidelines. In this work, several recombinant RBD proteins produced in five expression systems were characterized using a non-conventional protocol known as in-solution buffer-free digestion (BFD). In a single ESI-MS spectrum, BFD allowed very high sequence coverage (≥ 99%) and the detection of highly hydrophilic regions, including very short and hydrophilic peptides (2-8 amino acids), and the His6-tagged C-terminal peptide carrying several post-translational modifications at Cys538 such as cysteinylation, homocysteinylation, glutathionylation, truncated glutathionylation, and cyanylation, among others. The analysis using the conventional digestion protocol allowed lower sequence coverage (80-90%) and did not detect peptides carrying most of the above-mentioned PTMs. The two C-terminal peptides of a dimer [RBD(319-541)-(His)6]2 linked by an intermolecular disulfide bond (Cys538-Cys538) with twelve histidine residues were only detected by BFD. This protocol allows the detection of the four disulfide bonds present in the native RBD, low-abundance scrambling variants, free cysteine residues, O-glycoforms, and incomplete processing of the N-terminal end, if present. Artifacts generated by the in-solution BFD protocol were also characterized. BFD can be easily implemented; it has been applied to the characterization of the active pharmaceutical ingredient of two RBD-based vaccines, and we foresee that it can be also helpful to the characterization of mutated RBDs.


Subject(s)
Cysteine/metabolism , Peptide Fragments/metabolism , Protein Processing, Post-Translational , Spectrometry, Mass, Electrospray Ionization/methods , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Sequence , Cysteine/chemistry , Humans , Hydrophobic and Hydrophilic Interactions , Peptide Fragments/chemistry , Protein Binding , Protein Domains , Protein Subunits
4.
Eur J Clin Invest ; 51(11): e13661, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1398398

ABSTRACT

BACKGROUND: Unravelling autoimmune targets triggered by SARS-CoV-2 infection may provide crucial insights into the physiopathology of the disease and foster the development of potential therapeutic candidate targets and prognostic tools. We aimed at determining (a) the association between anti-SARS-CoV-2 and anti-apoA-1 humoral response and (b) the degree of linear homology between SARS-CoV-2, apoA-1 and Toll-like receptor 2 (TLR2) epitopes. DESIGN: Bioinformatics modelling coupled with mimic peptides engineering and competition experiments were used to assess epitopes sequence homologies. Anti-SARS-CoV-2 and anti-apoA-1 IgG as well as cytokines were assessed by immunoassays on a case-control (n = 101), an intensive care unit (ICU; n = 126) and a general population cohort (n = 663) with available samples in the pre and post-pandemic period. RESULTS: Using bioinformatics modelling, linear sequence homologies between apoA-1, TLR2 and Spike epitopes were identified but without experimental evidence of cross-reactivity. Overall, anti-apoA-1 IgG levels were higher in COVID-19 patients or anti-SARS-CoV-2 seropositive individuals than in healthy donors or anti-SARS-CoV-2 seronegative individuals (P < .0001). Significant and similar associations were noted between anti-apoA-1, anti-SARS-CoV-2 IgG, cytokines and lipid profile. In ICU patients, anti-SARS-CoV-2 and anti-apoA-1 seroconversion rates displayed similar 7-day kinetics, reaching 82% for anti-apoA-1 seropositivity. In the general population, SARS-CoV-2-exposed individuals displayed higher anti-apoA-1 IgG seropositivity rates than nonexposed ones (34% vs 16.8%; P = .004). CONCLUSION: COVID-19 induces a marked humoral response against the major protein of high-density lipoproteins. As a correlate of poorer prognosis in other clinical settings, such autoimmunity signatures may relate to long-term COVID-19 prognosis assessment and warrant further scrutiny in the current COVID-19 pandemic.


Subject(s)
Antibodies, Viral/immunology , Apolipoprotein A-I/immunology , Autoantibodies/immunology , COVID-19/immunology , Cytokines/immunology , Immunity, Humoral/immunology , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Aged, 80 and over , Apolipoprotein A-I/chemistry , Computational Biology , Epitopes/chemistry , Female , Humans , Immunoglobulin G/immunology , Male , Middle Aged , Peptide Fragments/chemistry , Peptide Fragments/immunology , Peptides , SARS-CoV-2 , Sequence Homology, Amino Acid , Spike Glycoprotein, Coronavirus/chemistry , Toll-Like Receptor 2/chemistry , Toll-Like Receptor 2/immunology , Young Adult
5.
STAR Protoc ; 2(3): 100635, 2021 09 17.
Article in English | MEDLINE | ID: covidwho-1386746

ABSTRACT

Understanding T-cell responses requires identifying viral peptides presented by human leukocyte antigens (HLAs). X-ray crystallography can be used to visualize their presentation. This protocol describes the expression, purification, and crystallization of HLA-A∗02:01, one of the most frequent HLA in the global population in complex with peptides derived from the SARS-CoV-2 nucleocapsid protein. This protocol can be applied to different HLA class I molecules bound to other peptides. For complete details on the use and execution of this protocol, please refer to Szeto et al. (2021).


Subject(s)
COVID-19/metabolism , Coronavirus Nucleocapsid Proteins/chemistry , HLA-A2 Antigen/chemistry , Peptide Fragments/chemistry , SARS-CoV-2/metabolism , T-Lymphocytes/immunology , COVID-19/immunology , COVID-19/virology , Coronavirus Nucleocapsid Proteins/isolation & purification , Coronavirus Nucleocapsid Proteins/metabolism , Crystallography, X-Ray , Epitopes, T-Lymphocyte/immunology , HLA-A2 Antigen/metabolism , Humans , Peptide Fragments/isolation & purification , Peptide Fragments/metabolism , Phosphoproteins/chemistry , Phosphoproteins/isolation & purification , Phosphoproteins/metabolism
6.
Viruses ; 13(8)2021 08 23.
Article in English | MEDLINE | ID: covidwho-1367926

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a global pandemic causing over 195 million infections and more than 4 million fatalities as of July 2021.To date, it has been demonstrated that a number of mutations in the spike glycoprotein (S protein) of SARS-CoV-2 variants of concern abrogate or reduce the neutralization potency of several therapeutic antibodies and vaccine-elicited antibodies. Therefore, the development of additional vaccine platforms with improved supply and logistic profile remains a pressing need. In this work, we have validated the applicability of a peptide-based strategy focused on a preventive as well as a therapeutic purpose. On the basis of the involvement of the dipeptidyl peptidase 4 (DPP4), in addition to the angiotensin converting enzyme 2 (ACE2) receptor in the mechanism of virus entry, we analyzed peptides bearing DPP4 sequences by protein-protein docking and assessed their ability to block pseudovirus infection in vitro. In parallel, we have selected and synthetized peptide sequences located within the highly conserved receptor-binding domain (RBD) of the S protein, and we found that RBD-based vaccines could better promote elicitation of high titers of neutralizing antibodies specific against the regions of interest, as confirmed by immunoinformatic methodologies and in vivo studies. These findings unveil a key antigenic site targeted by broadly neutralizing antibodies and pave the way to the design of pan-coronavirus vaccines.


Subject(s)
Dipeptidyl Peptidase 4/chemistry , Peptide Fragments/immunology , Peptide Fragments/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19/drug therapy , COVID-19/prevention & control , COVID-19 Vaccines/immunology , Chlorocebus aethiops , Dipeptidyl Peptidase 4/metabolism , Epitopes, T-Lymphocyte/immunology , Humans , Mice , Mice, Inbred BALB C , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Protein Binding , Protein Domains , Receptors, Coronavirus/chemistry , Receptors, Coronavirus/metabolism , SARS-CoV-2/chemistry , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Internalization
7.
Int J Mol Sci ; 22(15)2021 Jul 30.
Article in English | MEDLINE | ID: covidwho-1350316

ABSTRACT

Increasing evidence suggests that elderly people with dementia are vulnerable to the development of severe coronavirus disease 2019 (COVID-19). In Alzheimer's disease (AD), the major form of dementia, ß-amyloid (Aß) levels in the blood are increased; however, the impact of elevated Aß levels on the progression of COVID-19 remains largely unknown. Here, our findings demonstrate that Aß1-42, but not Aß1-40, bound to various viral proteins with a preferentially high affinity for the spike protein S1 subunit (S1) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the viral receptor, angiotensin-converting enzyme 2 (ACE2). These bindings were mainly through the C-terminal residues of Aß1-42. Furthermore, Aß1-42 strengthened the binding of the S1 of SARS-CoV-2 to ACE2 and increased the viral entry and production of IL-6 in a SARS-CoV-2 pseudovirus infection model. Intriguingly, data from a surrogate mouse model with intravenous inoculation of Aß1-42 show that the clearance of Aß1-42 in the blood was dampened in the presence of the extracellular domain of the spike protein trimers of SARS-CoV-2, whose effects can be prevented by a novel anti-Aß antibody. In conclusion, these findings suggest that the binding of Aß1-42 to the S1 of SARS-CoV-2 and ACE2 may have a negative impact on the course and severity of SARS-CoV-2 infection. Further investigations are warranted to elucidate the underlying mechanisms and examine whether reducing the level of Aß1-42 in the blood is beneficial to the fight against COVID-19 and AD.


Subject(s)
Amyloid beta-Peptides/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Peptide Fragments/metabolism , SARS-CoV-2/enzymology , Spike Glycoprotein, Coronavirus/metabolism , A549 Cells , Alzheimer Disease/complications , Alzheimer Disease/metabolism , Amyloid beta-Peptides/chemistry , Animals , COVID-19/complications , COVID-19/metabolism , Chlorocebus aethiops , Humans , Interleukin-6/metabolism , Mice, Inbred C57BL , Mice, Transgenic , Peptide Fragments/chemistry , Protein Subunits/chemistry , Protein Subunits/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Vero Cells , Virus Internalization
8.
Int J Mol Sci ; 22(15)2021 Jul 30.
Article in English | MEDLINE | ID: covidwho-1335101

ABSTRACT

Increasing evidence suggests that elderly people with dementia are vulnerable to the development of severe coronavirus disease 2019 (COVID-19). In Alzheimer's disease (AD), the major form of dementia, ß-amyloid (Aß) levels in the blood are increased; however, the impact of elevated Aß levels on the progression of COVID-19 remains largely unknown. Here, our findings demonstrate that Aß1-42, but not Aß1-40, bound to various viral proteins with a preferentially high affinity for the spike protein S1 subunit (S1) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the viral receptor, angiotensin-converting enzyme 2 (ACE2). These bindings were mainly through the C-terminal residues of Aß1-42. Furthermore, Aß1-42 strengthened the binding of the S1 of SARS-CoV-2 to ACE2 and increased the viral entry and production of IL-6 in a SARS-CoV-2 pseudovirus infection model. Intriguingly, data from a surrogate mouse model with intravenous inoculation of Aß1-42 show that the clearance of Aß1-42 in the blood was dampened in the presence of the extracellular domain of the spike protein trimers of SARS-CoV-2, whose effects can be prevented by a novel anti-Aß antibody. In conclusion, these findings suggest that the binding of Aß1-42 to the S1 of SARS-CoV-2 and ACE2 may have a negative impact on the course and severity of SARS-CoV-2 infection. Further investigations are warranted to elucidate the underlying mechanisms and examine whether reducing the level of Aß1-42 in the blood is beneficial to the fight against COVID-19 and AD.


Subject(s)
Amyloid beta-Peptides/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Peptide Fragments/metabolism , SARS-CoV-2/enzymology , Spike Glycoprotein, Coronavirus/metabolism , A549 Cells , Alzheimer Disease/complications , Alzheimer Disease/metabolism , Amyloid beta-Peptides/chemistry , Animals , COVID-19/complications , COVID-19/metabolism , Chlorocebus aethiops , Humans , Interleukin-6/metabolism , Mice, Inbred C57BL , Mice, Transgenic , Peptide Fragments/chemistry , Protein Subunits/chemistry , Protein Subunits/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Vero Cells , Virus Internalization
9.
Biomolecules ; 11(7)2021 07 19.
Article in English | MEDLINE | ID: covidwho-1328091

ABSTRACT

Proteins of the major histocompatibility complex (MHC) class I, or human leukocyte antigen (HLA) in humans interact with endogenous peptides and present them to T cell receptors (TCR), which in turn tune the immune system to recognize and discriminate between self and foreign (non-self) peptides. Of especial importance are peptides derived from tumor-associated antigens. T cells recognizing these peptides are found in cancer patients, but not in cancer-free individuals. What stimulates this recognition, which is vital for the success of checkpoint based therapy? A peptide derived from the protein p53 (residues 161-169 or p161) was reported to show this behavior. T cells recognizing this unmodified peptide could be further stimulated in vitro to create effective cancer killing CTLs (cytotoxic T lymphocytes). We hypothesize that the underlying difference may arise from post-translational glycosylation of p161 in normal individuals, likely masking it against recognition by TCR. Defects in glycosylation in cancer cells may allow the presentation of the native peptide. We investigate the structural consequences of such peptide glycosylation by investigating the associated structural dynamics.


Subject(s)
HLA-A24 Antigen/chemistry , HLA-A24 Antigen/metabolism , Receptors, Antigen, T-Cell/metabolism , Tumor Suppressor Protein p53/metabolism , Acetylglucosamine/metabolism , Glycosylation , Human Immunodeficiency Virus Proteins/chemistry , Human Immunodeficiency Virus Proteins/metabolism , Humans , Hydrogen Bonding , Models, Molecular , Molecular Dynamics Simulation , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Protein Conformation , Receptors, Antigen, T-Cell/chemistry , Tumor Suppressor Protein p53/chemistry
10.
Chem Commun (Camb) ; 57(57): 6979-6982, 2021 Jul 15.
Article in English | MEDLINE | ID: covidwho-1287828

ABSTRACT

The infection of coronavirus initiates with the binding between its spike protein receptor binding domain (RBD) and a human cellular receptor called angiotensin-converting enzyme 2 (ACE2). Here, we construct truncated ACE2 peptide-conjugated gold nanoparticles as antiviral scaffolds and study their binding with the SARS-CoV-2 RBD using dynamic light scattering (DLS). Systematic DLS analysis identifies the effective peptide-nanoparticle conjugation and its efficient, specific, and long-lasting multivalent binding towards the RBD with a binding affinity of 41 nM, indicating the potential of this antiviral platform to compete with natural ACE2-RBD interactions for viral blocking and showcasing an accessible approach to measure the binding constants and kinetics.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Nanoparticles/chemistry , Peptide Fragments/chemistry , Peptide Fragments/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Dynamic Light Scattering , Molecular Dynamics Simulation , Protein Binding , Protein Domains , Substrate Specificity
11.
Protein Expr Purif ; 183: 105861, 2021 07.
Article in English | MEDLINE | ID: covidwho-1117500

ABSTRACT

Sensitive and specific serology tests are essential for epidemiological and public health studies of COVID-19 and for vaccine efficacy testing. The presence of antibodies to SARS-CoV-2 surface glycoprotein (Spike) and, specifically, its receptor-binding domain (RBD) correlates with inhibition of SARS-CoV-2 binding to the cellular receptor and viral entry into the cells. Serology tests that detect antibodies targeting RBD have high potential to predict COVID-19 immunity and to accurately determine the extent of the vaccine-induced immune response. Cost-effective methods of expression and purification of Spike and its fragments that preserve antigenic properties are essential for development of such tests. Here we describe a method of production of His6-tagged S319-640 fragment containing RBD in E. coli. It includes expression of the fragment, solubilization of inclusion bodies, and on-the-column refolding. The antigenic properties of the resulting product are similar, but not identical to the RBD-containing fragment expressed in human cells.


Subject(s)
COVID-19/virology , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Binding Sites , Cloning, Molecular , Escherichia coli/chemistry , Escherichia coli/genetics , Gene Expression , Humans , Peptide Fragments/chemistry , Peptide Fragments/genetics , Peptide Fragments/isolation & purification , Protein Domains , Protein Refolding , SARS-CoV-2/genetics , Solubility , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/isolation & purification
12.
Sci Signal ; 14(665)2021 01 12.
Article in English | MEDLINE | ID: covidwho-1066811

ABSTRACT

The spike protein of SARS-CoV-2 binds the angiotensin-converting enzyme 2 (ACE2) on the host cell surface and subsequently enters host cells through receptor-mediated endocytosis. Additional cell receptors may be directly or indirectly involved, including integrins. The cytoplasmic tails of ACE2 and integrins contain several predicted short linear motifs (SLiMs) that may facilitate internalization of the virus as well as its subsequent propagation through processes such as autophagy. Here, we measured the binding affinity of predicted interactions between SLiMs in the cytoplasmic tails of ACE2 and integrin ß3 with proteins that mediate endocytic trafficking and autophagy. We validated that a class I PDZ-binding motif mediated binding of ACE2 to the scaffolding proteins SNX27, NHERF3, and SHANK, and that a binding site for the clathrin adaptor AP2 µ2 in ACE2 overlaps with a phospho-dependent binding site for the SH2 domains of Src family tyrosine kinases. Furthermore, we validated that an LC3-interacting region (LIR) in integrin ß3 bound to the ATG8 domains of the autophagy receptors MAP1LC3 and GABARAP in a manner enhanced by LIR-adjacent phosphorylation. Our results provide molecular links between cell receptors and mediators of endocytosis and autophagy that may facilitate viral entry and propagation.


Subject(s)
Angiotensin-Converting Enzyme 2/physiology , COVID-19/virology , Integrin beta3/physiology , Receptors, Virus/physiology , SARS-CoV-2/physiology , SARS-CoV-2/pathogenicity , Virus Internalization , Amino Acid Sequence , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/genetics , Autophagy/physiology , Endocytosis/physiology , Host Microbial Interactions/genetics , Host Microbial Interactions/physiology , Humans , Integrin beta3/chemistry , Integrin beta3/genetics , Models, Molecular , Pandemics , Peptide Fragments/chemistry , Peptide Fragments/genetics , Peptide Fragments/physiology , Phosphorylation , Protein Binding , Protein Interaction Domains and Motifs , Protein Sorting Signals/genetics , Protein Sorting Signals/physiology , Receptors, Virus/chemistry , Receptors, Virus/genetics , SARS-CoV-2/genetics
13.
J Proteome Res ; 19(11): 4393-4397, 2020 11 06.
Article in English | MEDLINE | ID: covidwho-960279

ABSTRACT

The detection of viral RNA by polymerase chain reaction (PCR) is currently the main diagnostic tool for COVID-19 ( Eurosurveillance 2019, 25 (3), 1). The PCR-based test, however, shows limited sensitivity, especially in the early and late stages of disease development ( Nature 2020, 581, 465-469; J. Formosan Med. Assoc. 2020, 119 (6) 1123), and is relatively time-consuming. Fast and reliable complementary methods for detecting the viral infection would be of help in the current pandemic conditions. Mass spectrometry is one of such possibilities. We have developed a mass-spectrometry-based method for the detection of the SARS CoV-2 virus in nasopharynx epithelial swabs based on the detection of the viral nucleocapsid N protein. Our approach shows confident identification of the N protein in patient samples, even those with the lowest viral loads, and a much simpler preparation procedure. Our main protocol consists of virus inactivation by heating and the addition of isopropanol and tryptic digestion of the proteins sedimented from the swabs followed by MS analysis. A set of unique peptides, produced as a result of proteolysis of the nucleocapsid phosphoprotein of SARS-CoV-2, is detected. The obtained results can further be used to create fast parallel mass-spectrometric approaches for the detection of the virus in the nasopharyngeal mucosa, saliva, sputum and other physiological fluids.


Subject(s)
Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Mass Spectrometry/methods , Nasopharynx/virology , Nucleocapsid Proteins/analysis , Pneumonia, Viral/diagnosis , Betacoronavirus/chemistry , COVID-19 , COVID-19 Testing , Coronavirus Infections/virology , Coronavirus Nucleocapsid Proteins , Humans , Nasal Mucosa/virology , Pandemics , Peptide Fragments/analysis , Peptide Fragments/chemistry , Phosphoproteins , Pneumonia, Viral/virology , Proteomics , SARS-CoV-2 , Viral Load
14.
J Proteome Res ; 19(11): 4389-4392, 2020 11 06.
Article in English | MEDLINE | ID: covidwho-960268

ABSTRACT

Mass spectrometry (MS) can deliver valuable diagnostic data that complement genomic information and allow us to increase our current knowledge of the COVID-19 disease caused by the SARS-CoV-2 virus. We developed a simple, MS-based method to specifically detect SARS-CoV-2 proteins from gargle solution samples of COVID-19 patients. The protocol consists of an acetone precipitation and tryptic digestion of proteins contained within the gargle solution, followed by a targeted MS analysis. Our methodology identifies unique peptides originating from SARS-CoV-2 nucleoprotein. Building on these promising initial results, faster MS protocols can now be developed as routine diagnostic tools for COVID-19 patients. Data are available via ProteomeXchange with identifier PXD019423.


Subject(s)
Betacoronavirus/chemistry , Coronavirus Infections/diagnosis , Mass Spectrometry/methods , Mouth/virology , Pneumonia, Viral/diagnosis , COVID-19 , COVID-19 Testing , Chromatography, High Pressure Liquid , Clinical Laboratory Techniques , Coronavirus Infections/virology , Humans , Nucleoproteins/analysis , Nucleoproteins/chemistry , Pandemics , Peptide Fragments/analysis , Peptide Fragments/chemistry , Pneumonia, Viral/virology , SARS-CoV-2 , Viral Proteins/analysis , Viral Proteins/chemistry
15.
Adv Drug Deliv Rev ; 167: 47-65, 2020 12.
Article in English | MEDLINE | ID: covidwho-921794

ABSTRACT

To date, no effective vaccines or therapies are available against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pandemic agent of the coronavirus disease 2019 (COVID-19). Due to their safety, efficacy and specificity, peptide inhibitors hold great promise for the treatment of newly emerging viral pathogens. Based on the known structures of viral proteins and their cellular targets, antiviral peptides can be rationally designed and optimized. The resulting peptides may be highly specific for their respective targets and particular viral pathogens or exert broad antiviral activity. Here, we summarize the current status of peptides inhibiting SARS-CoV-2 entry and outline the strategies used to design peptides targeting the ACE2 receptor or the viral spike protein and its activating proteases furin, transmembrane serine protease 2 (TMPRSS2), or cathepsin L. In addition, we present approaches used against related viruses such as SARS-CoV-1 that might be implemented for inhibition of SARS-CoV-2 infection.


Subject(s)
Antiviral Agents/administration & dosage , COVID-19/drug therapy , COVID-19/metabolism , Peptide Fragments/administration & dosage , SARS-CoV-2/drug effects , SARS-CoV-2/metabolism , Amino Acid Sequence , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/metabolism , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Drug Delivery Systems/methods , Humans , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Protein Binding/drug effects , Protein Binding/physiology , Protein Structure, Secondary , Protein Structure, Tertiary , Serine Endopeptidases/metabolism , Serine Proteinase Inhibitors/administration & dosage , Serine Proteinase Inhibitors/chemistry , Serine Proteinase Inhibitors/metabolism
16.
Science ; 370(6518): 861-865, 2020 11 13.
Article in English | MEDLINE | ID: covidwho-883300

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), uses the viral spike (S) protein for host cell attachment and entry. The host protease furin cleaves the full-length precursor S glycoprotein into two associated polypeptides: S1 and S2. Cleavage of S generates a polybasic Arg-Arg-Ala-Arg carboxyl-terminal sequence on S1, which conforms to a C-end rule (CendR) motif that binds to cell surface neuropilin-1 (NRP1) and NRP2 receptors. We used x-ray crystallography and biochemical approaches to show that the S1 CendR motif directly bound NRP1. Blocking this interaction by RNA interference or selective inhibitors reduced SARS-CoV-2 entry and infectivity in cell culture. NRP1 thus serves as a host factor for SARS-CoV-2 infection and may potentially provide a therapeutic target for COVID-19.


Subject(s)
Betacoronavirus/physiology , Neuropilin-1/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Virus Internalization , Amino Acid Motifs , Angiotensin-Converting Enzyme 2 , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/metabolism , COVID-19 , Caco-2 Cells , Coronavirus Infections/virology , Crystallography, X-Ray , Furin/metabolism , HeLa Cells , Humans , Mutagenesis, Site-Directed , Neuropilin-1/antagonists & inhibitors , Neuropilin-1/chemistry , Neuropilin-1/genetics , Pandemics , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Protein Binding , Protein Interaction Domains and Motifs , RNA Interference , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics
17.
Nat Commun ; 11(1): 5047, 2020 10 07.
Article in English | MEDLINE | ID: covidwho-841208

ABSTRACT

COVID-19, caused by SARS-CoV-2, lacks effective therapeutics. Additionally, no antiviral drugs or vaccines were developed against the closely related coronavirus, SARS-CoV-1 or MERS-CoV, despite previous zoonotic outbreaks. To identify starting points for such therapeutics, we performed a large-scale screen of electrophile and non-covalent fragments through a combined mass spectrometry and X-ray approach against the SARS-CoV-2 main protease, one of two cysteine viral proteases essential for viral replication. Our crystallographic screen identified 71 hits that span the entire active site, as well as 3 hits at the dimer interface. These structures reveal routes to rapidly develop more potent inhibitors through merging of covalent and non-covalent fragment hits; one series of low-reactivity, tractable covalent fragments were progressed to discover improved binders. These combined hits offer unprecedented structural and reactivity information for on-going structure-based drug design against SARS-CoV-2 main protease.


Subject(s)
Betacoronavirus/chemistry , Cysteine Endopeptidases/chemistry , Peptide Fragments/chemistry , Viral Nonstructural Proteins/chemistry , Betacoronavirus/enzymology , Binding Sites , Catalytic Domain , Coronavirus 3C Proteases , Crystallography, X-Ray , Cysteine Endopeptidases/metabolism , Drug Design , Mass Spectrometry , Models, Molecular , Peptide Fragments/metabolism , Protein Conformation , SARS-CoV-2 , Small Molecule Libraries/chemistry , Small Molecule Libraries/metabolism , Static Electricity , Viral Nonstructural Proteins/metabolism
18.
J Comput Aided Mol Des ; 34(12): 1237-1259, 2020 12.
Article in English | MEDLINE | ID: covidwho-841071

ABSTRACT

Computational protein-ligand docking is well-known to be prone to inaccuracies in input receptor structures, and it is challenging to obtain good docking results with computationally predicted receptor structures (e.g. through homology modeling). Here we introduce a fragment-based docking method and test if it reduces requirements on the accuracy of an input receptor structures relative to non-fragment docking approaches. In this method, small rigid fragments are docked first using AutoDock Vina to generate a large number of favorably docked poses spanning the receptor binding pocket. Then a graph theory maximum clique algorithm is applied to find combined sets of docked poses of different fragment types onto which the complete ligand can be properly aligned. On the basis of these alignments, possible binding poses of complete ligand are determined. This docking method is first tested for bound docking on a series of Cytochrome P450 (CYP450) enzyme-substrate complexes, in which experimentally determined receptor structures are used. For all complexes tested, ligand poses of less than 1 Å root mean square deviations (RMSD) from the actual binding positions can be recovered. Then the method is tested for unbound docking with modeled receptor structures for a number of protein-ligand complexes from different families including the very recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protease. For all complexes, poses with RMSD less than 3 Å from actual binding positions can be recovered. Our results suggest that for docking with approximately modeled receptor structures, fragment-based methods can be more effective than common complete ligand docking approaches.


Subject(s)
Betacoronavirus/enzymology , Coronavirus Infections/drug therapy , Cysteine Endopeptidases/drug effects , Molecular Docking Simulation , Pandemics , Pneumonia, Viral/drug therapy , Viral Nonstructural Proteins/drug effects , ATPases Associated with Diverse Cellular Activities/chemistry , ATPases Associated with Diverse Cellular Activities/metabolism , COVID-19 , Coronavirus 3C Proteases , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/metabolism , Cytochrome P-450 Enzyme System/chemistry , Cytochrome P-450 Enzyme System/metabolism , DNA-Binding Proteins/chemistry , DNA-Binding Proteins/metabolism , Humans , Ligands , Models, Chemical , Models, Molecular , Molecular Chaperones/chemistry , Molecular Chaperones/metabolism , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Protein Binding , Protein Conformation , Receptors, G-Protein-Coupled/chemistry , Receptors, G-Protein-Coupled/metabolism , SARS-CoV-2 , Transcription Factors/chemistry , Transcription Factors/metabolism , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism
19.
Biomolecules ; 10(9)2020 08 26.
Article in English | MEDLINE | ID: covidwho-822256

ABSTRACT

In Trichomonas vaginalis (T. vaginalis), cyclophilins play a vital role in dislodging Myb proteins from the membrane compartment and leading them to nuclear translocation. We previously reported that TvCyP1 cyclophilin from T. vaginalis forms a dimer and plays an essential role in moving the Myb1 transcription factor toward the nucleus. In comparison, TvCyP2 containing an extended segment at the N-terminus (N-terminal segment) formed a monomer and showed a different role in regulating protein trafficking. Four X-ray structures of TvCyP2 were determined under various conditions, all showing the N-terminal segment interacting with the active site of a neighboring TvCyP2, an unusual interaction. NMR study revealed that this particular interaction exists in solution as well and also the N-terminal segment seems to interact with the membrane. In vivo study of TvCyP2 and TvCyP2-∆N (TvCyP2 without the N-terminal segment) indicated that both proteins have different subcellular localization. Together, the structural and functional characteristics at the N-terminal segment offer valuable information for insights into the mechanism of how TvCyP2 regulates protein trafficking, which may be applied in drug development to prevent pathogenesis and disease progression in T. vaginalis infection.


Subject(s)
Cyclophilins/chemistry , Cyclophilins/metabolism , Protozoan Proteins/metabolism , Trichomonas vaginalis/metabolism , Active Transport, Cell Nucleus , Amino Acid Sequence , Binding Sites , Crystallography, X-Ray , Cyclophilins/genetics , Endoplasmic Reticulum/metabolism , Humans , Magnetic Resonance Spectroscopy , Models, Molecular , Peptide Fragments/chemistry , Peptide Fragments/genetics , Peptide Fragments/metabolism , Protein Conformation, alpha-Helical , Protein Interaction Domains and Motifs , Protein Stability , Protein Transport , Protozoan Proteins/chemistry , Protozoan Proteins/genetics , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sequence Homology, Amino Acid , Transcription Factors/metabolism , Trichomonas vaginalis/genetics
20.
Biochim Biophys Acta Biomembr ; 1862(7): 183274, 2020 07 01.
Article in English | MEDLINE | ID: covidwho-820155

ABSTRACT

The gp41 type I membrane protein is part of the trimeric Env complex forming the spikes at the HIV surface. By interacting with cellular receptors, the Env protein complex initiates the infectious cycle of HIV. After the first contact has been established Env disassembles by shedding gp120 while the remaining gp41 undergoes a number of conformational changes which drive fusion of the cellular and the viral membranes. Here we investigated the membrane interactions and oligomerization of the two gp41 heptad repeat domains NHR and CHR. While these are thought to form a six-helix bundle in the post-fusion state little is known about their structure and role during prior fusion events. When investigated in aqueous buffer by CD and fluorescence quenching techniques the formation of NHR/CHR hetero-oligomers is detected. An equilibrium of monomers and hetero-oligomers is also observed in membrane environments. Furthermore, the partitioning to POPC or POPC/POPG 3/1 vesicles of the two domains alone or in combination has been studied. The membrane interactions were further characterized by 15N solid-state NMR spectroscopy of uniaxially oriented samples which shows that the polypeptide helices are oriented parallel to the bilayer surface. The 31P solid-state NMR spectra of the same samples are indicative of considerable disordering of the membrane packing. The data support models where NHR and CHR insert in the viral and cellular membranes, respectively, where they exhibit an active role in the membrane fusion events.


Subject(s)
HIV Envelope Protein gp41/ultrastructure , HIV Infections/genetics , HIV-1/genetics , Membrane Fusion/genetics , Cell Membrane/genetics , Cell Membrane/virology , HIV Envelope Protein gp41/chemistry , HIV Envelope Protein gp41/genetics , HIV Infections/virology , HIV-1/pathogenicity , Humans , Magnetic Resonance Spectroscopy , Peptide Fragments/chemistry , Peptide Fragments/genetics , Protein Conformation
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