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1.
Int J Mol Sci ; 21(14)2020 Jul 11.
Article in English | MEDLINE | ID: covidwho-646270

ABSTRACT

A dodecadepsipeptide valinomycin (VLM) has been most recently reported to be a potential anti-coronavirus drug that could be efficiently produced on a large scale. It is thus of importance to study solid-phase forms of VLM in order to be able to ensure its polymorphic purity in drug formulations. The previously available solid-state NMR (SSNMR) data are combined with the plane-wave DFT computations in the NMR crystallography framework. Structural/spectroscopical predictions (the PBE functional/GIPAW method) are obtained to characterize four polymorphs of VLM. Interactions which confer a conformational stability to VLM molecules in these crystalline forms are described in detail. The way how various structural factors affect the values of SSNMR parameters is thoroughly analyzed, and several SSNMR markers of the respective VLM polymorphs are identified. The markers are connected to hydrogen bonding effects upon the corresponding (13C/15N/1H) isotropic chemical shifts of (CO, Namid, Hamid, Hα) VLM backbone nuclei. These results are expected to be crucial for polymorph control of VLM and in probing its interactions in dosage forms.


Subject(s)
Magnetic Resonance Spectroscopy/methods , Valinomycin/chemistry , Betacoronavirus/chemistry , Betacoronavirus/isolation & purification , Betacoronavirus/metabolism , Carbon Isotopes/chemistry , Coronavirus Infections/pathology , Coronavirus Infections/virology , Crystallography , Hydrogen Bonding , Nitrogen Isotopes/chemistry , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Valinomycin/metabolism
2.
J Phys Chem B ; 124(34): 7336-7347, 2020 08 27.
Article in English | MEDLINE | ID: covidwho-752578

ABSTRACT

The 2019 novel coronavirus (SARS-CoV-2) epidemic, which was first reported in December 2019 in Wuhan, China, was declared a pandemic by the World Health Organization in March 2020. Genetically, SARS-CoV-2 is closely related to SARS-CoV, which caused a global epidemic with 8096 confirmed cases in more than 25 countries from 2002 to 2003. Given the significant morbidity and mortality rate, the current pandemic poses a danger to all of humanity, prompting us to understand the activity of SARS-CoV-2 at the atomic level. Experimental studies have revealed that spike proteins of both SARS-CoV-2 and SARS-CoV bind to angiotensin-converting enzyme 2 (ACE2) before entering the cell for replication. However, the binding affinities reported by different groups seem to contradict each other. Wrapp et al. (Science 2020, 367, 1260-1263) showed that the spike protein of SARS-CoV-2 binds to the ACE2 peptidase domain (ACE2-PD) more strongly than does SARS-CoV, and this fact may be associated with a greater severity of the new virus. However, Walls et al. (Cell 2020, 181, 281-292) reported that SARS-CoV-2 exhibits a higher binding affinity, but the difference between the two variants is relatively small. To understand the binding mechnism and experimental results, we investigated how the receptor binding domain (RBD) of SARS-CoV (SARS-CoV-RBD) and SARS-CoV-2 (SARS-CoV-2-RBD) interacts with a human ACE2-PD using molecular modeling. We applied a coarse-grained model to calculate the dissociation constant and found that SARS-CoV-2 displays a 2-fold higher binding affinity. Using steered all-atom molecular dynamics simulations, we demonstrate that, like a coarse-grained simulation, SARS-CoV-2-RBD was associated with ACE2-PD more strongly than was SARS-CoV-RBD, as evidenced by a higher rupture force and larger pulling work. We show that the binding affinity of both viruses to ACE2 is driven by electrostatic interactions.


Subject(s)
Betacoronavirus/chemistry , Peptidyl-Dipeptidase A/metabolism , Receptors, Virus/metabolism , SARS Virus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Humans , Molecular Dynamics Simulation , Mutation , Protein Binding , Spike Glycoprotein, Coronavirus/genetics , Static Electricity
3.
In Vivo ; 34(5): 3023-3026, 2020.
Article in English | MEDLINE | ID: covidwho-740631

ABSTRACT

BACKGROUND/AIM: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). One drug that has attracted interest is the antiparasitic compound ivermectin, a macrocyclic lactone derived from the bacterium Streptomyces avermitilis. We carried out a docking study to determine if ivermectin might be able to attach to the SARS-CoV-2 spike receptor-binding domain bound with ACE2. MATERIALS AND METHODS: We used the program AutoDock Vina Extended to perform the docking study. RESULTS: Ivermectin docked in the region of leucine 91 of the spike and histidine 378 of the ACE2 receptor. The binding energy of ivermectin to the spike-ACE2 complex was -18 kcal/mol and binding constant was 5.8 e-08. CONCLUSION: The ivermectin docking we identified may interfere with the attachment of the spike to the human cell membrane. Clinical trials now underway should determine whether ivermectin is an effective treatment for SARS-Cov2 infection.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Ivermectin/chemistry , Peptidyl-Dipeptidase A/chemistry , Pneumonia, Viral/drug therapy , Betacoronavirus/chemistry , Betacoronavirus/pathogenicity , Binding Sites/drug effects , Cell Membrane/drug effects , Coronavirus Infections/virology , Drug Repositioning , Histidine/chemistry , Humans , Ivermectin/therapeutic use , Leucine/chemistry , Molecular Docking Simulation , Pandemics , Peptidyl-Dipeptidase A/drug effects , Pneumonia, Viral/virology , Streptomyces/chemistry
4.
Molecules ; 25(17)2020 Aug 28.
Article in English | MEDLINE | ID: covidwho-740497

ABSTRACT

A pandemic caused by the novel coronavirus (SARS-CoV-2 or COVID-19) began in December 2019 in Wuhan, China, and the number of newly reported cases continues to increase. More than 19.7 million cases have been reported globally and about 728,000 have died as of this writing (10 August 2020). Recently, it has been confirmed that the SARS-CoV-2 main protease (Mpro) enzyme is responsible not only for viral reproduction but also impedes host immune responses. The Mpro provides a highly favorable pharmacological target for the discovery and design of inhibitors. Currently, no specific therapies are available, and investigations into the treatment of COVID-19 are lacking. Therefore, herein, we analyzed the bioactive phytocompounds isolated by gas chromatography-mass spectroscopy (GC-MS) from Tinospora crispa as potential COVID-19 Mpro inhibitors, using molecular docking study. Our analyses unveiled that the top nine hits might serve as potential anti-SARS-CoV-2 lead molecules, with three of them exerting biological activity and warranting further optimization and drug development to combat COVID-19.


Subject(s)
Antiviral Agents/chemistry , Betacoronavirus/chemistry , Phytochemicals/chemistry , Protease Inhibitors/chemistry , Tinospora/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/classification , Antiviral Agents/isolation & purification , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Betacoronavirus/enzymology , Catalytic Domain , Coronavirus Infections/drug therapy , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/genetics , Cysteine Endopeptidases/metabolism , Drug Discovery , Gas Chromatography-Mass Spectrometry , Gene Expression , Humans , Kinetics , Molecular Docking Simulation , Pandemics , Phytochemicals/classification , Phytochemicals/isolation & purification , Phytochemicals/pharmacology , Pneumonia, Viral/drug therapy , Protease Inhibitors/classification , Protease Inhibitors/isolation & purification , Protease Inhibitors/pharmacology , Protein Binding , Protein Interaction Domains and Motifs , Protein Structure, Secondary , Substrate Specificity , Thermodynamics , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism
5.
Molecules ; 25(17)2020 Aug 27.
Article in English | MEDLINE | ID: covidwho-737517

ABSTRACT

Three types of new coronaviruses (CoVs) have been identified recently as the causative viruses for the severe pneumonia-like respiratory illnesses, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and corona-virus disease 2019 (COVID-19). Neither therapeutic agents nor vaccines have been developed to date, which is a major drawback in controlling the present global pandemic of COVID-19 caused by SARS coronavirus 2 (SARS-CoV-2) and has resulted in more than 20,439,814 cases and 744,385 deaths. Each of the 3C-like (3CL) proteases of the three CoVs is essential for the proliferation of the CoVs, and an inhibitor of the 3CL protease (3CLpro) is thought to be an ideal therapeutic agent against SARS, MERS, or COVID-19. Among these, SARS-CoV is the first corona-virus isolated and has been studied in detail since the first pandemic in 2003. This article briefly reviews a series of studies on SARS-CoV, focusing on the development of inhibitors for the SARS-CoV 3CLpro based on molecular interactions with the 3CL protease. Our recent approach, based on the structure-based rational design of a novel scaffold for SARS-CoV 3CLpro inhibitor, is also included. The achievements summarized in this short review would be useful for the design of a variety of novel inhibitors for corona-viruses, including SARS-CoV-2.


Subject(s)
Antiviral Agents/chemistry , Betacoronavirus/chemistry , Middle East Respiratory Syndrome Coronavirus/pathogenicity , Protease Inhibitors/chemistry , SARS Virus/pathogenicity , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/classification , Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Betacoronavirus/enzymology , Catalytic Domain , Coronavirus Infections/drug therapy , Crystallography, X-Ray , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/genetics , Cysteine Endopeptidases/metabolism , Humans , Kinetics , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/metabolism , Molecular Docking Simulation , Pandemics , Pneumonia, Viral/drug therapy , Protease Inhibitors/classification , Protease Inhibitors/therapeutic use , Protein Binding , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Protein Interaction Domains and Motifs , SARS Virus/genetics , SARS Virus/metabolism , Severe Acute Respiratory Syndrome/drug therapy , Substrate Specificity , Thermodynamics , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism
6.
J Chem Phys ; 153(7): 075101, 2020 Aug 21.
Article in English | MEDLINE | ID: covidwho-726966

ABSTRACT

In 2020, the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions of people worldwide and caused the coronavirus disease 2019 (COVID-19). Spike (S) glycoproteins on the viral membrane bind to ACE2 receptors on the host cell membrane and initiate fusion, and S protein is currently among the primary drug target to inhibit viral entry. The S protein can be in a receptor inaccessible (closed) or accessible (open) state based on down and up positions of its receptor-binding domain (RBD), respectively. However, conformational dynamics and the transition pathway between closed to open states remain unexplored. Here, we performed all-atom molecular dynamics (MD) simulations starting from closed and open states of the S protein trimer in the presence of explicit water and ions. MD simulations showed that RBD forms a higher number of interdomain interactions and exhibits lower mobility in its down position than its up position. MD simulations starting from intermediate conformations between the open and closed states indicated that RBD switches to the up position through a semi-open intermediate that potentially reduces the free energy barrier between the closed and open states. Free energy landscapes were constructed, and a minimum energy pathway connecting the closed and open states was proposed. Because RBD-ACE2 binding is compatible with the semi-open state, but not with the closed state of the S protein, we propose that the formation of the intermediate state is a prerequisite for the host cell recognition.


Subject(s)
Betacoronavirus/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Binding Sites , Hydrogen Bonding , Models, Chemical , Molecular Dynamics Simulation , Peptidyl-Dipeptidase A/chemistry , Peptidyl-Dipeptidase A/metabolism , Principal Component Analysis , Protein Binding , Protein Conformation , Protein Domains , Receptors, Virus/chemistry , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Thermodynamics
7.
Sci Rep ; 10(1): 14031, 2020 08 20.
Article in English | MEDLINE | ID: covidwho-724696

ABSTRACT

The COVID-19 pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), was declared on March 11, 2020 by the World Health Organization. As of the 31st of May, 2020, there have been more than 6 million COVID-19 cases diagnosed worldwide and over 370,000 deaths, according to Johns Hopkins. Thousands of SARS-CoV-2 strains have been sequenced to date, providing a valuable opportunity to investigate the evolution of the virus on a global scale. We performed a phylogenetic analysis of over 1,225 SARS-CoV-2 genomes spanning from late December 2019 to mid-March 2020. We identified a missense mutation, D614G, in the spike protein of SARS-CoV-2, which has emerged as a predominant clade in Europe (954 of 1,449 (66%) sequences) and is spreading worldwide (1,237 of 2,795 (44%) sequences). Molecular dating analysis estimated the emergence of this clade around mid-to-late January (10-25 January) 2020. We also applied structural bioinformatics to assess the potential impact of D614G on the virulence and epidemiology of SARS-CoV-2. In silico analyses on the spike protein structure suggests that the mutation is most likely neutral to protein function as it relates to its interaction with the human ACE2 receptor. The lack of clinical metadata available prevented our investigation of association between viral clade and disease severity phenotype. Future work that can leverage clinical outcome data with both viral and human genomic diversity is needed to monitor the pandemic.


Subject(s)
Betacoronavirus/chemistry , Coronavirus Infections/epidemiology , Evolution, Molecular , Pneumonia, Viral/epidemiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Base Sequence , Betacoronavirus/pathogenicity , Child , Child, Preschool , Computer Simulation , Coronavirus Infections/virology , Female , Genome, Viral/genetics , Humans , Infant , Male , Middle Aged , Mutation, Missense , Pandemics , Peptidyl-Dipeptidase A/metabolism , Phylogeny , Pneumonia, Viral/virology , Protein Conformation , Spike Glycoprotein, Coronavirus/metabolism , Virulence/genetics , Young Adult
8.
J Infect Dev Ctries ; 14(7): 691-695, 2020 07 31.
Article in English | MEDLINE | ID: covidwho-721537

ABSTRACT

As the incidence of Coronavirus Disease 19 (COVID-19) continues to rise, many countries have been seeking for medical assistance such as donation or procurement of laboratory test kits and strips. These consumables are largely intended for use in the laboratory investigations of COVID-19 cases, suspected contacts, asymptomatic persons and in discharging cured persons. Thus, this article was instigated to update and remind healthcare providers and policymakers (especially those in developing countries) on the principles of sample collections, storage, transportation, laboratory protocols and networks needed for appropriate public health response against COVID-19 pandemic in Africa and other developing countries. In addition, this article presents challenges that hinder adequate COVID-19 laboratory response and discuss some possible solutions that could ameliorate these constrains.


Subject(s)
Betacoronavirus , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Laboratories , Pneumonia, Viral/diagnosis , Specimen Handling , Africa/epidemiology , Betacoronavirus/chemistry , Betacoronavirus/genetics , Betacoronavirus/immunology , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Epidemiological Monitoring , Humans , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , Public Health , Reverse Transcriptase Polymerase Chain Reaction/methods , Serologic Tests
9.
Viruses ; 12(9)2020 08 19.
Article in English | MEDLINE | ID: covidwho-721525

ABSTRACT

COVID-19 novel coronavirus (CoV) disease caused by severe acquired respiratory syndrome (SARS)-CoV-2 manifests severe lethal respiratory illness in humans and has recently developed into a worldwide pandemic. The lack of effective treatment strategy and vaccines against the SARS-CoV-2 poses a threat to human health. An extremely high infection rate and multi-organ secondary infection within a short period of time makes this virus more deadly and challenging for therapeutic interventions. Despite high sequence similarity and utilization of common host-cell receptor, human angiotensin-converting enzyme-2 (ACE2) for virus entry, SARS-CoV-2 is much more infectious than SARS-CoV. Structure-based sequence comparison of the N-terminal domain (NTD) of the spike protein of Middle East respiratory syndrome (MERS)-CoV, SARS-CoV, and SARS-CoV-2 illustrate three divergent loop regions in SARS-CoV-2, which is reminiscent of MERS-CoV sialoside binding pockets. Comparative binding analysis with host sialosides revealed conformational flexibility of SARS-CoV-2 divergent loop regions to accommodate diverse glycan-rich sialosides. These key differences with SARS-CoV and similarity with MERS-CoV suggest an evolutionary adaptation of SARS-CoV-2 spike glycoprotein reciprocal interaction with host surface sialosides to infect host cells with wide tissue tropism.


Subject(s)
Betacoronavirus/chemistry , Middle East Respiratory Syndrome Coronavirus/chemistry , Sialic Acids/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Amino Sugars/metabolism , Betacoronavirus/physiology , Binding Sites , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , N-Acetylneuraminic Acid/metabolism , Protein Binding , Protein Domains , Receptors, Virus/chemistry , Receptors, Virus/metabolism , SARS Virus/chemistry , Sialyl Lewis X Antigen/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Viral Tropism , Virus Internalization
10.
Sci Rep ; 10(1): 13866, 2020 08 17.
Article in English | MEDLINE | ID: covidwho-720849

ABSTRACT

The Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). The virus has rapidly spread in humans, causing the ongoing Coronavirus pandemic. Recent studies have shown that, similarly to SARS-CoV, SARS-CoV-2 utilises the Spike glycoprotein on the envelope to recognise and bind the human receptor ACE2. This event initiates the fusion of viral and host cell membranes and then the viral entry into the host cell. Despite several ongoing clinical studies, there are currently no approved vaccines or drugs that specifically target SARS-CoV-2. Until an effective vaccine is available, repurposing FDA approved drugs could significantly shorten the time and reduce the cost compared to de novo drug discovery. In this study we attempted to overcome the limitation of in silico virtual screening by applying a robust in silico drug repurposing strategy. We combined and integrated docking simulations, with molecular dynamics (MD), Supervised MD (SuMD) and Steered MD (SMD) simulations to identify a Spike protein - ACE2 interaction inhibitor. Our data showed that Simeprevir and Lumacaftor bind the receptor-binding domain of the Spike protein with high affinity and prevent ACE2 interaction.


Subject(s)
Betacoronavirus/drug effects , Computational Biology/methods , Coronavirus Infections/metabolism , Drug Discovery/methods , Drug Repositioning/methods , Pneumonia, Viral/metabolism , Aminopyridines/pharmacology , Benzodioxoles/pharmacology , Betacoronavirus/chemistry , Binding Sites , Coronavirus Infections/virology , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Pandemics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Protein Binding/drug effects , Protein Conformation , Protein Domains/drug effects , Protein Interaction Maps/drug effects , Simeprevir/pharmacology , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Spike Glycoprotein, Coronavirus/metabolism
11.
Front Cell Infect Microbiol ; 10: 405, 2020.
Article in English | MEDLINE | ID: covidwho-719722

ABSTRACT

The spread of the novel coronavirus (SARS-CoV-2) has triggered a global emergency, that demands urgent solutions for detection and therapy to prevent escalating health, social, and economic impacts. The spike protein (S) of this virus enables binding to the human receptor ACE2, and hence presents a prime target for vaccines preventing viral entry into host cells. The S proteins from SARS and SARS-CoV-2 are similar, but structural differences in the receptor binding domain (RBD) preclude the use of SARS-specific neutralizing antibodies to inhibit SARS-CoV-2. Here we used comparative pangenomic analysis of all sequenced reference Betacoronaviruses, complemented with functional and structural analyses. This analysis reveals that, among all core gene clusters present in these viruses, the envelope protein E shows a variant cluster shared by SARS and SARS-CoV-2 with two completely-conserved key functional features, namely an ion-channel, and a PDZ-binding motif (PBM). These features play a key role in the activation of the inflammasome causing the acute respiratory distress syndrome, the leading cause of death in SARS and SARS-CoV-2 infections. Together with functional pangenomic analysis, mutation tracking, and previous evidence, on E protein as a determinant of pathogenicity in SARS, we suggest E protein as an alternative therapeutic target to be considered for further studies to reduce complications of SARS-CoV-2 infections in COVID-19.


Subject(s)
Betacoronavirus/chemistry , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/genetics , Coronavirus Infections/virology , Genes, Essential , Genes, Viral , Genome, Viral , Humans , Middle East Respiratory Syndrome Coronavirus/chemistry , Middle East Respiratory Syndrome Coronavirus/genetics , Mutation , Open Reading Frames , PDZ Domains , Pandemics , Pneumonia, Viral/virology , Protein Domains , SARS Virus/chemistry
12.
Viruses ; 12(8)2020 08 07.
Article in English | MEDLINE | ID: covidwho-713633

ABSTRACT

Rapid large-scale testing is essential for controlling the ongoing pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The standard diagnostic pipeline for testing SARS-CoV-2 presence in patients with an ongoing infection is predominantly based on pharyngeal swabs, from which the viral RNA is extracted using commercial kits, followed by reverse transcription and quantitative PCR detection. As a result of the large demand for testing, commercial RNA extraction kits may be limited and, alternatively, non-commercial protocols are needed. Here, we provide a magnetic bead RNA extraction protocol that is predominantly based on in-house made reagents and is performed in 96-well plates supporting large-scale testing. Magnetic bead RNA extraction was benchmarked against the commercial QIAcube extraction platform. Comparable viral RNA detection sensitivity and specificity were obtained by fluorescent and colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) using a primer set targeting the N gene, as well as RT-qPCR using a primer set targeting the E gene, showing that the RNA extraction protocol presented here can be combined with a variety of detection methods at high throughput. Importantly, the presented diagnostic workflow can be quickly set up in a laboratory without access to an automated pipetting robot.


Subject(s)
Betacoronavirus/chemistry , Betacoronavirus/genetics , Clinical Laboratory Techniques/methods , Coronavirus Infections/virology , Pneumonia, Viral/virology , RNA, Viral/isolation & purification , Betacoronavirus/isolation & purification , Coronavirus Infections/diagnosis , Humans , Magnetic Phenomena , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , Pandemics , Pneumonia, Viral/diagnosis , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Reverse Transcription , Sensitivity and Specificity
13.
PLoS One ; 15(8): e0237418, 2020.
Article in English | MEDLINE | ID: covidwho-713417

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has crudely demonstrated the need for massive and rapid diagnostics. By the first week of July, more than 10,000,000 positive cases of COVID-19 have been reported worldwide, although this number could be greatly underestimated. In the case of an epidemic emergency, the first line of response should be based on commercially available and validated resources. Here, we demonstrate the use of the miniPCR, a commercial compact and portable PCR device recently available on the market, in combination with a commercial well-plate reader as a diagnostic system for detecting genetic material of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19. We used the miniPCR to detect and amplify SARS-CoV-2 DNA sequences using the sets of initiators recommended by the World Health Organization (WHO) for targeting three different regions that encode for the N protein. Prior to amplification, samples were combined with a DNA intercalating reagent (i.e., EvaGreen Dye). Sample fluorescence after amplification was then read using a commercial 96-well plate reader. This straightforward method allows the detection and amplification of SARS-CoV-2 nucleic acids in the range of ~625 to 2×105 DNA copies. The accuracy and simplicity of this diagnostics strategy may provide a cost-efficient and reliable alternative for COVID-19 pandemic testing, particularly in underdeveloped regions where RT-QPCR instrument availability may be limited. The portability, ease of use, and reproducibility of the miniPCR makes it a reliable alternative for deployment in point-of-care SARS-CoV-2 detection efforts during pandemics.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Point-of-Care Systems , Polymerase Chain Reaction/instrumentation , Polymerase Chain Reaction/methods , Base Sequence , Betacoronavirus/chemistry , Coronavirus Infections/virology , DNA, Viral/genetics , Data Accuracy , Humans , Nucleocapsid Proteins/genetics , Pandemics , Pneumonia, Viral/virology , Polymerase Chain Reaction/economics , Reproducibility of Results , Sensitivity and Specificity
14.
Anal Chem ; 92(17): 11520-11524, 2020 09 01.
Article in English | MEDLINE | ID: covidwho-713341

ABSTRACT

The traditional approach for analyzing interaction data from biosensors instruments is based on the simplified assumption that also larger biomolecules interactions are homogeneous. It was recently reported that the human receptor angiotensin-converting enzyme 2 (ACE2) plays a key role for capturing SARS-CoV-2 into the human target body, and binding studies were performed using biosensors techniques based on surface plasmon resonance and bio-layer interferometry. The published affinity constants for the interactions, derived using the traditional approach, described a single interaction between ACE2 and the SARS-CoV-2 receptor binding domain (RBD). We reanalyzed these data sets using our advanced four-step approach based on an adaptive interaction distribution algorithm (AIDA) that accounts for the great complexity of larger biomolecules and gives a two-dimensional distribution of association and dissociation rate constants. Our results showed that in both cases the standard assumption about a single interaction was erroneous, and in one of the cases, the value of the affinity constant KD differed more than 300% between the reported value and our calculation. This information can prove very useful in providing mechanistic information and insights about the mechanism of interactions between ACE2 and SARS-CoV-2 RBD or similar systems.


Subject(s)
Betacoronavirus/chemistry , Interferometry/statistics & numerical data , Peptidyl-Dipeptidase A/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Surface Plasmon Resonance/statistics & numerical data , Algorithms , Humans , Kinetics , Ligands , Peptidyl-Dipeptidase A/chemistry , Protein Binding , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry
15.
PLoS One ; 15(8): e0237300, 2020.
Article in English | MEDLINE | ID: covidwho-710429

ABSTRACT

The outbreak of COVID-19 across the world has posed unprecedented and global challenges on multiple fronts. Most of the vaccine and drug development has focused on the spike proteins and viral RNA-polymerases and main protease for viral replication. Using the bioinformatics and structural modelling approach, we modelled the structure of the envelope (E)-protein of novel SARS-CoV-2. The E-protein of this virus shares sequence similarity with that of SARS- CoV-1, and is highly conserved in the N-terminus regions. Incidentally, compared to spike proteins, E proteins demonstrate lower disparity and mutability among the isolated sequences. Using homology modelling, we found that the most favorable structure could function as a gated ion channel conducting H+ ions. Combining pocket estimation and docking with water, we determined that GLU 8 and ASN 15 in the N-terminal region were in close proximity to form H-bonds which was further validated by insertion of the E protein in an ERGIC-mimic membrane. Additionally, two distinct "core" structures were visible, the hydrophobic core and the central core, which may regulate the opening/closing of the channel. We propose this as a mechanism of viral ion channeling activity which plays a critical role in viral infection and pathogenesis. In addition, it provides a structural basis and additional avenues for vaccine development and generating therapeutic interventions against the virus.


Subject(s)
Betacoronavirus/chemistry , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/genetics , Betacoronavirus/isolation & purification , Computer Simulation , Coronavirus Infections/virology , Humans , Hydrogen , Hydrogen Bonding , Magnetic Resonance Spectroscopy , Models, Molecular , Pneumonia, Viral/virology , Point Mutation , Protein Conformation , Structural Homology, Protein , Vaccines, Attenuated , Vaccines, Inactivated , Viral Envelope Proteins/immunology , Viral Vaccines , Water/chemistry
16.
ACS Nano ; 14(8): 10616-10623, 2020 08 25.
Article in English | MEDLINE | ID: covidwho-696515

ABSTRACT

The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein plays a crucial role in binding the human cell receptor ACE2 that is required for viral entry. Many studies have been conducted to target the structures of RBD-ACE2 binding and to design RBD-targeting vaccines and drugs. Nevertheless, mutations distal from the SARS-CoV-2 RBD also impact its transmissibility and antibody can target non-RBD regions, suggesting the incomplete role of the RBD region in the spike protein-ACE2 binding. Here, in order to elucidate distant binding mechanisms, we analyze complexes of ACE2 with the wild-type spike protein and with key mutants via large-scale all-atom explicit solvent molecular dynamics simulations. We find that though distributed approximately 10 nm away from the RBD, the SARS-CoV-2 polybasic cleavage sites enhance, via electrostatic interactions and hydration, the RBD-ACE2 binding affinity. A negatively charged tetrapeptide (GluGluLeuGlu) is then designed to neutralize the positively charged arginine on the polybasic cleavage sites. We find that the tetrapeptide GluGluLeuGlu binds to one of the three polybasic cleavage sites of the SARS-CoV-2 spike protein lessening by 34% the RBD-ACE2 binding strength. This significant binding energy reduction demonstrates the feasibility to neutralize RBD-ACE2 binding by targeting this specific polybasic cleavage site. Our work enhances understanding of the binding mechanism of SARS-CoV-2 to ACE2, which may aid the design of therapeutics for COVID-19 infection.


Subject(s)
Betacoronavirus/metabolism , Coronavirus Infections/virology , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Substitution , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Betacoronavirus/chemistry , Betacoronavirus/genetics , Binding Sites/genetics , Drug Design , Host Microbial Interactions/drug effects , Humans , Molecular Dynamics Simulation , Mutation , Oligopeptides/chemistry , Oligopeptides/pharmacology , Pandemics , Peptidyl-Dipeptidase A/chemistry , Peptidyl-Dipeptidase A/genetics , Protein Binding/drug effects , Protein Binding/genetics , Protein Binding/physiology , Protein Domains , Receptors, Virus/chemistry , Receptors, Virus/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Virus Internalization
17.
J Phys Chem B ; 124(34): 7336-7347, 2020 08 27.
Article in English | MEDLINE | ID: covidwho-696364

ABSTRACT

The 2019 novel coronavirus (SARS-CoV-2) epidemic, which was first reported in December 2019 in Wuhan, China, was declared a pandemic by the World Health Organization in March 2020. Genetically, SARS-CoV-2 is closely related to SARS-CoV, which caused a global epidemic with 8096 confirmed cases in more than 25 countries from 2002 to 2003. Given the significant morbidity and mortality rate, the current pandemic poses a danger to all of humanity, prompting us to understand the activity of SARS-CoV-2 at the atomic level. Experimental studies have revealed that spike proteins of both SARS-CoV-2 and SARS-CoV bind to angiotensin-converting enzyme 2 (ACE2) before entering the cell for replication. However, the binding affinities reported by different groups seem to contradict each other. Wrapp et al. (Science 2020, 367, 1260-1263) showed that the spike protein of SARS-CoV-2 binds to the ACE2 peptidase domain (ACE2-PD) more strongly than does SARS-CoV, and this fact may be associated with a greater severity of the new virus. However, Walls et al. (Cell 2020, 181, 281-292) reported that SARS-CoV-2 exhibits a higher binding affinity, but the difference between the two variants is relatively small. To understand the binding mechnism and experimental results, we investigated how the receptor binding domain (RBD) of SARS-CoV (SARS-CoV-RBD) and SARS-CoV-2 (SARS-CoV-2-RBD) interacts with a human ACE2-PD using molecular modeling. We applied a coarse-grained model to calculate the dissociation constant and found that SARS-CoV-2 displays a 2-fold higher binding affinity. Using steered all-atom molecular dynamics simulations, we demonstrate that, like a coarse-grained simulation, SARS-CoV-2-RBD was associated with ACE2-PD more strongly than was SARS-CoV-RBD, as evidenced by a higher rupture force and larger pulling work. We show that the binding affinity of both viruses to ACE2 is driven by electrostatic interactions.


Subject(s)
Betacoronavirus/chemistry , Peptidyl-Dipeptidase A/metabolism , Receptors, Virus/metabolism , SARS Virus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Humans , Molecular Dynamics Simulation , Mutation , Protein Binding , Spike Glycoprotein, Coronavirus/genetics , Static Electricity
18.
Phys Chem Chem Phys ; 22(33): 18272-18283, 2020 Sep 07.
Article in English | MEDLINE | ID: covidwho-695147

ABSTRACT

The COVID-19 pandemic poses a severe threat to human health with unprecedented social and economic disruption. Spike (S) glycoprotein in the SARS-CoV-2 virus is pivotal in understanding the virus anatomy, since it initiates the early contact with the ACE2 receptor in the human cell. The subunit S1 in chain A of S-protein has four structural domains: the receptor binding domain (RBD), the n-terminal domain (NTD) and two subdomains (SD1, SD2). We report details of the intra- and inter-molecular binding mechanism of RBD using density functional theory, including electronic structure, interatomic bonding and partial charge distribution. We identify five strong hydrogen bonds and analyze their roles in binding. This provides a pathway to a quantum-chemical understanding of the interaction between the S-protein and the ACE2 receptor with insights into the function of conserved features in the ACE2 receptor binding domain that could inform vaccine and drug development.


Subject(s)
Betacoronavirus/chemistry , Peptidyl-Dipeptidase A/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Sequence , Density Functional Theory , Humans , Hydrogen Bonding , Models, Chemical , Peptidyl-Dipeptidase A/chemistry , Protein Binding , Protein Domains , Sequence Alignment , Spike Glycoprotein, Coronavirus/chemistry
19.
Structure ; 28(8): 874-878, 2020 08 04.
Article in English | MEDLINE | ID: covidwho-692175

ABSTRACT

During global pandemics, the spread of information needs to be faster than the spread of the virus in order to ensure the health and safety of human populations worldwide. In our current crisis, the demand for SARS-CoV-2 drugs and vaccines highlights the importance of biological targets and their three-dimensional shape. In particular, structural biology as a field was poised to quickly respond to crises due to previous experience and expertise and because of its early adoption of open access practices.


Subject(s)
Betacoronavirus/chemistry , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , Viral Proteins/chemistry , Cysteine Endopeptidases/chemistry , Databases, Protein , Humans , Models, Molecular , Molecular Biology , Protein Conformation , RNA Replicase/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Viral Nonstructural Proteins/chemistry
20.
Nanoscale ; 12(31): 16409-16413, 2020 Aug 21.
Article in English | MEDLINE | ID: covidwho-690863

ABSTRACT

We report on the novel observation about the gain in nanomechanical stability of the SARS-CoV-2 (CoV2) spike (S) protein in comparison with SARS-CoV from 2002 (CoV1). Our findings have several biological implications in the subfamily of coronaviruses, as they suggest that the receptor binding domain (RBD) (∼200 amino acids) plays a fundamental role as a damping element of the massive viral particle's motion prior to cell-recognition, while also facilitating viral attachment, fusion and entry. The mechanical stability via pulling of the RBD is 250 pN and 200 pN for CoV2 and CoV1 respectively, and the additional stability observed for CoV2 (∼50 pN) might play a role in the increasing spread of COVID-19.


Subject(s)
Betacoronavirus/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Amino Acid Sequence , Binding Sites , Humans , Molecular Dynamics Simulation , Peptidyl-Dipeptidase A/metabolism , Protein Binding , Protein Domains , Protein Stability , SARS Virus/chemistry , Species Specificity , Spike Glycoprotein, Coronavirus/metabolism
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