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1.
J Virol ; 94(13)2020 06 16.
Article in English | MEDLINE | ID: covidwho-760222

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
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.
Nat Commun ; 11(1): 4303, 2020 08 27.
Article in English | MEDLINE | ID: covidwho-733523

ABSTRACT

The novel highly transmissible human coronavirus SARS-CoV-2 is the causative agent of the COVID-19 pandemic. Thus far, there is no approved therapeutic drug specifically targeting this emerging virus. Here we report the isolation and characterization of a panel of human neutralizing monoclonal antibodies targeting the SARS-CoV-2 receptor binding domain (RBD). These antibodies were selected from a phage display library constructed using peripheral circulatory lymphocytes collected from patients at the acute phase of the disease. These neutralizing antibodies are shown to recognize distinct epitopes on the viral spike RBD. A subset of the antibodies exert their inhibitory activity by abrogating binding of the RBD to the human ACE2 receptor. The human monoclonal antibodies described here represent a promising basis for the design of efficient combined post-exposure therapy for SARS-CoV-2 infection.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , Antibodies, Viral/immunology , Antibodies, Viral/metabolism , Betacoronavirus/metabolism , Chlorocebus aethiops , Epitope Mapping , Epitopes , Humans , Peptide Library , Peptidyl-Dipeptidase A/metabolism , Protein Binding , Protein Interaction Domains and Motifs , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells
4.
Sci Rep ; 10(1): 14214, 2020 08 26.
Article in English | MEDLINE | ID: covidwho-733506

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a major public health concern. A handful of static structures now provide molecular insights into how SARS-CoV-2 and SARS-CoV interact with its host target, which is the angiotensin converting enzyme 2 (ACE2). Molecular recognition, binding and function are dynamic processes. To evaluate this, multiple 500 ns or 1 µs all-atom molecular dynamics simulations were performed to better understand the structural stability and interfacial interactions between the receptor binding domain of the spike (S) protein of SARS-CoV-2 and SARS-CoV bound to ACE2. Several contacts were observed to form, break and reform in the interface during the simulations. Our results indicate that SARS-CoV-2 and SARS-CoV utilizes unique strategies to achieve stable binding to ACE2. Several differences were observed between the residues of SARS-CoV-2 and SARS-CoV that consistently interacted with ACE2. Notably, a stable salt bridge between Lys417 of SARS-CoV-2 S protein and Asp30 of ACE2 as well as three stable hydrogen bonds between Tyr449, Gln493 and Gln498 of SARS-CoV-2 and Asp38, Glu35 and Lys353 of ACE2 were observed, which were absent in the ACE2-SARS-CoV interface. Some previously reported residues, which were suggested to enhance the binding affinity of SARS-CoV-2, were not observed to form stable interactions in these simulations. Molecular mechanics-generalized Born surface area based free energy of binding was observed to be higher for SARS-CoV-2 in all simulations. Stable binding to the host receptor is crucial for virus entry. Therefore, special consideration should be given to these stable interactions while designing potential drugs and treatment modalities to target or disrupt this interface.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/metabolism , Coronavirus Infections/virology , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/metabolism , Pneumonia, Viral/virology , SARS Virus/physiology , Severe Acute Respiratory Syndrome/virology , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Sequence , Binding Sites , Conserved Sequence , Host-Pathogen Interactions , Humans , Models, Molecular , Pandemics , Peptidyl-Dipeptidase A/chemistry , Protein Binding , Protein Conformation , Spike Glycoprotein, Coronavirus/chemistry
5.
BMC Res Notes ; 13(1): 398, 2020 Aug 27.
Article in English | MEDLINE | ID: covidwho-733023

ABSTRACT

OBJECTIVE: In December 2019 a novel coronavirus (SARS-CoV-2) that is causing the current COVID-19 pandemic was identified in Wuhan, China. Many questions have been raised about its origin and adaptation to humans. In the present work we performed a genetic analysis of the Spike glycoprotein (S) of SARS-CoV-2 and other related coronaviruses (CoVs) isolated from different hosts in order to trace the evolutionary history of this protein and the adaptation of SARS-CoV-2 to humans. RESULTS: Based on the sequence analysis of the S gene, we suggest that the origin of SARS-CoV-2 is the result of recombination events between bat and pangolin CoVs. The hybrid SARS-CoV-2 ancestor jumped to humans and has been maintained by natural selection. Although the S protein of RaTG13 bat CoV has a high nucleotide identity with the S protein of SARS-CoV-2, the phylogenetic tree and the haplotype network suggest a non-direct parental relationship between these CoVs. Moreover, it is likely that the basic function of the receptor-binding domain (RBD) of S protein was acquired by the SARS-CoV-2 from the MP789 pangolin CoV by recombination and it has been highly conserved.


Subject(s)
Betacoronavirus/genetics , Coronaviridae/genetics , Recombination, Genetic , Spike Glycoprotein, Coronavirus/genetics , Adaptation, Biological/genetics , Animals , Binding Sites/genetics , Chiroptera/virology , Eutheria/virology , Evolution, Molecular , Furin/metabolism , Host Specificity , Humans , Peptidyl-Dipeptidase A/metabolism , Phylogeny , Selection, Genetic , Spike Glycoprotein, Coronavirus/metabolism
6.
Cell Physiol Biochem ; 54(4): 767-790, 2020 Aug 25.
Article in English | MEDLINE | ID: covidwho-729851

ABSTRACT

The pandemic of the severe acute respiratory syndrome coronavirus (SARS-CoV)-2 at the end of 2019 marked the third outbreak of a highly pathogenic coronavirus affecting the human population in the past twenty years. Cross-species zoonotic transmission of SARS-CoV-2 has caused severe pathogenicity and led to more than 655,000 fatalities worldwide until July 28, 2020. Outbursts of this virus underlined the importance of controlling infectious pathogens across international frontiers. Unfortunately, there is currently no clinically approved antiviral drug or vaccine against SARS-CoV-2, although several broad-spectrum antiviral drugs targeting multiple RNA viruses have shown a positive response and improved recovery in patients. In this review, we compile our current knowledge of the emergence, transmission, and pathogenesis of SARS-CoV-2 and explore several features of SARS-CoV-2. We emphasize the current therapeutic approaches used to treat infected patients. We also highlight the results of in vitro and in vivo data from several studies, which have broadened our knowledge of potential drug candidates for the successful treatment of patients infected with and discuss possible virus and host-based treatment options against SARS-CoV-2.


Subject(s)
Betacoronavirus , Coronavirus Infections , Pandemics , Pneumonia, Viral , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Betacoronavirus/genetics , Betacoronavirus/physiology , Coronaviridae/pathogenicity , Coronaviridae Infections/epidemiology , Coronaviridae Infections/virology , Coronavirus Infections/drug therapy , Coronavirus Infections/epidemiology , Coronavirus Infections/prevention & control , Coronavirus Infections/therapy , Coronavirus Infections/transmission , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/prevention & control , Cytokines/antagonists & inhibitors , Drug Delivery Systems , Endocytosis/drug effects , Forecasting , Genome, Viral , Global Health , Humans , Immunity, Herd , Immunization, Passive , Pandemics/prevention & control , Peptide Hydrolases/pharmacology , Peptide Hydrolases/therapeutic use , Pneumonia, Viral/drug therapy , Pneumonia, Viral/epidemiology , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , RNA, Viral/genetics , Receptors, Virus/antagonists & inhibitors , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Spike Glycoprotein, Coronavirus/metabolism , Viral Vaccines , Virus Internalization/drug effects , Virus Replication/drug effects , Zoonoses
7.
PLoS Pathog ; 16(8): e1008762, 2020 08.
Article in English | MEDLINE | ID: covidwho-727333

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a newly emerging, highly transmissible, and pathogenic coronavirus in humans that has caused global public health emergencies and economic crises. To date, millions of infections and thousands of deaths have been reported worldwide, and the numbers continue to rise. Currently, there is no specific drug or vaccine against this deadly virus; therefore, there is a pressing need to understand the mechanism(s) through which this virus enters the host cell. Viral entry into the host cell is a multistep process in which SARS-CoV-2 utilizes the receptor-binding domain (RBD) of the spike (S) glycoprotein to recognize angiotensin-converting enzyme 2 (ACE2) receptors on the human cells; this initiates host-cell entry by promoting viral-host cell membrane fusion through large-scale conformational changes in the S protein. Receptor recognition and fusion are critical and essential steps of viral infections and are key determinants of the viral host range and cross-species transmission. In this review, we summarize the current knowledge on the origin and evolution of SARS-CoV-2 and the roles of key viral factors. We discuss the structure of RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 and its significance in drug discovery and explain the receptor recognition mechanisms of coronaviruses. Further, we provide a comparative analysis of the SARS-CoV and SARS-CoV-2 S proteins and their receptor-binding specificity and discuss the differences in their antigenicity based on biophysical and structural characteristics.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/virology , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/virology , Spike Glycoprotein, Coronavirus/metabolism , Animals , Coronavirus Infections/metabolism , Humans , Pandemics , Pneumonia, Viral/metabolism , Receptors, Virus/immunology , Receptors, Virus/metabolism , Spike Glycoprotein, Coronavirus/immunology , Virus Internalization
8.
J Transl Med ; 18(1): 321, 2020 08 24.
Article in English | MEDLINE | ID: covidwho-727282

ABSTRACT

BACKGROUND: The outbreak of coronavirus disease (COVID-19) was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), through its surface spike glycoprotein (S-protein) recognition on the receptor Angiotensin-converting enzyme 2 (ACE2) in humans. However, it remains unclear how genetic variations in ACE2 may affect its function and structure, and consequently alter the recognition by SARS-CoV-2. METHODS: We have systemically characterized missense variants in the gene ACE2 using data from the Genome Aggregation Database (gnomAD; N = 141,456). To investigate the putative deleterious role of missense variants, six existing functional prediction tools were applied to evaluate their impact. We further analyzed the structural flexibility of ACE2 and its protein-protein interface with the S-protein of SARS-CoV-2 using our developed Legion Interfaces Analysis (LiAn) program. RESULTS: Here, we characterized a total of 12 ACE2 putative deleterious missense variants. Of those 12 variants, we further showed that p.His378Arg could directly weaken the binding of catalytic metal atom to decrease ACE2 activity and p.Ser19Pro could distort the most important helix to the S-protein. Another seven missense variants may affect secondary structures (i.e. p.Gly211Arg; p.Asp206Gly; p.Arg219Cys; p.Arg219His, p.Lys341Arg, p.Ile468Val, and p.Ser547Cys), whereas p.Ile468Val with AF = 0.01 is only present in Asian. CONCLUSIONS: We provide strong evidence of putative deleterious missense variants in ACE2 that are present in specific populations, which could disrupt the function and structure of ACE2. These findings provide novel insight into the genetic variation in ACE2 which may affect the SARS-CoV-2 recognition and infection, and COVID-19 susceptibility and treatment.


Subject(s)
Betacoronavirus/physiology , Mutation, Missense , Peptidyl-Dipeptidase A/genetics , Protein Interaction Domains and Motifs/genetics , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Substitution , Betacoronavirus/metabolism , Binding Sites/genetics , Coronavirus Infections/ethnology , Coronavirus Infections/genetics , Coronavirus Infections/virology , DNA Mutational Analysis/methods , Databases, Genetic , Genetic Predisposition to Disease/ethnology , Genetic Variation , Geography , Humans , Models, Molecular , Molecular Docking Simulation , Pandemics , Peptidyl-Dipeptidase A/chemistry , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/ethnology , Pneumonia, Viral/genetics , Pneumonia, Viral/virology , Polymorphism, Single Nucleotide , Protein Binding , Protein Structure, Secondary/genetics , Spike Glycoprotein, Coronavirus/chemistry , Virus Internalization
9.
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
10.
Int J Mol Sci ; 21(17)2020 Aug 20.
Article in English | MEDLINE | ID: covidwho-725462

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor, angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), and furin, which promote entry of the virus into the host cell, have been identified as determinants of SARS-CoV-2 infection. Dorsal tongue and gingiva, saliva, and tongue coating samples were examined to determine the presence of these molecules in the oral cavity. Immunohistochemical analyses showed that ACE2 was expressed in the stratified squamous epithelium of the dorsal tongue and gingiva. TMPRSS2 was strongly expressed in stratified squamous epithelium in the keratinized surface layer and detected in the saliva and tongue coating samples via Western blot. Furin was localized mainly in the lower layer of stratified squamous epithelium and detected in the saliva but not tongue coating. ACE2, TMPRSS2, and furin mRNA expression was observed in taste bud-derived cultured cells, which was similar to the immunofluorescence observations. These data showed that essential molecules for SARS-CoV-2 infection were abundant in the oral cavity. However, the database analysis showed that saliva also contains many protease inhibitors. Therefore, although the oral cavity may be the entry route for SARS-CoV-2, other factors including protease inhibitors in the saliva that inhibit viral entry should be considered.


Subject(s)
Betacoronavirus/metabolism , Furin/metabolism , Mouth Mucosa/metabolism , Peptidyl-Dipeptidase A/metabolism , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Coronavirus Infections/metabolism , Gingiva/metabolism , Humans , Pandemics , Pneumonia, Viral/metabolism , Saliva/metabolism , Tongue/metabolism , Virus Internalization
11.
Int J Mol Sci ; 21(17)2020 Aug 19.
Article in English | MEDLINE | ID: covidwho-724888

ABSTRACT

The aim of this study is to examine the use of an inflammasome competitor as a preventative agent. Coronaviruses have zoonotic potential due to the adaptability of their S protein to bind receptors of other species, most notably demonstrated by SARS-CoV. The binding of SARS-CoV-2 to TLR (Toll-like receptor) causes the release of pro-IL-1ß, which is cleaved by caspase-1, followed by the formation and activation of the inflammasome, which is a mediator of lung inflammation, fever, and fibrosis. The NLRP3 (NACHT, LRR and PYD domains-containing protein 3) inflammasome is implicated in a variety of human diseases including Alzheimer's disease (AD), prion diseases, type 2 diabetes, and numerous infectious diseases. By examining the use of 4,4'-diaminodiphenyl sulfone (DDS) in the treatment of patients with Hansen's disease, also diagnosed as Alzheimer's disease, this study demonstrates the diverse mechanisms involved in the activation of inflammasomes. TLRs, due to genetic polymorphisms, can alter the immune response to a wide variety of microbial ligands, including viruses. In particular, TLR2Arg677Trp was reported to be exclusively present in Korean patients with lepromatous leprosy (LL). Previously, mutation of the intracellular domain of TLR2 has demonstrated its role in determining the susceptibility to LL, though LL was successfully treated using a combination of DDS with rifampicin and clofazimine. Of the three tested antibiotics, DDS was effective in the molecular regulation of NLRP3 inflammasome activators that are important in mild cognitive impairment (MCI), Parkinson's disease (PD), and AD. The specific targeting of NLRP3 itself or up-/downstream factors of the NLRP3 inflammasome by DDS may be responsible for its observed preventive effects, functioning as a competitor.


Subject(s)
Coronavirus Infections/drug therapy , Dapsone/pharmacology , Inflammasomes/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Pneumonia, Viral/drug therapy , Alzheimer Disease/pathology , Clofazimine/pharmacology , Cognitive Dysfunction/pathology , Humans , Interleukin-1beta/metabolism , Leprosy/drug therapy , Leprosy/genetics , Pandemics , Parkinsonian Disorders/pathology , Rifampin/pharmacology , Spike Glycoprotein, Coronavirus/metabolism , Toll-Like Receptor 2/genetics
12.
Sci Rep ; 10(1): 14004, 2020 08 19.
Article in English | MEDLINE | ID: covidwho-724698

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a novel evolutionary divergent RNA virus, is responsible for the present devastating COVID-19 pandemic. To explore the genomic signatures, we comprehensively analyzed 2,492 complete and/or near-complete genome sequences of SARS-CoV-2 strains reported from across the globe to the GISAID database up to 30 March 2020. Genome-wide annotations revealed 1,516 nucleotide-level variations at different positions throughout the entire genome of SARS-CoV-2. Moreover, nucleotide (nt) deletion analysis found twelve deletion sites throughout the genome other than previously reported deletions at coding sequence of the ORF8 (open reading frame), spike, and ORF7a proteins, specifically in polyprotein ORF1ab (n = 9), ORF10 (n = 1), and 3´-UTR (n = 2). Evidence from the systematic gene-level mutational and protein profile analyses revealed a large number of amino acid (aa) substitutions (n = 744), demonstrating the viral proteins heterogeneous. Notably, residues of receptor-binding domain (RBD) showing crucial interactions with angiotensin-converting enzyme 2 (ACE2) and cross-reacting neutralizing antibody were found to be conserved among the analyzed virus strains, except for replacement of lysine with arginine at 378th position of the cryptic epitope of a Shanghai isolate, hCoV-19/Shanghai/SH0007/2020 (EPI_ISL_416320). Furthermore, our results of the preliminary epidemiological data on SARS-CoV-2 infections revealed that frequency of aa mutations were relatively higher in the SARS-CoV-2 genome sequences of Europe (43.07%) followed by Asia (38.09%), and North America (29.64%) while case fatality rates remained higher in the European temperate countries, such as Italy, Spain, Netherlands, France, England and Belgium. Thus, the present method of genome annotation employed at this early pandemic stage could be a promising tool for monitoring and tracking the continuously evolving pandemic situation, the associated genetic variants, and their implications for the development of effective control and prophylaxis strategies.


Subject(s)
Betacoronavirus/classification , Betacoronavirus/genetics , Coronavirus Infections/epidemiology , Genetic Heterogeneity , Genome, Viral/genetics , Genome-Wide Association Study/methods , Global Health , Pneumonia, Viral/epidemiology , Amino Acid Sequence/genetics , Antibodies, Neutralizing/immunology , Base Pair Mismatch , Base Sequence/genetics , Climate , Coronavirus Infections/virology , Humans , Open Reading Frames/genetics , Pandemics , Peptidyl-Dipeptidase A/metabolism , Phylogeny , Pneumonia, Viral/virology , Protein Domains/genetics , Protein Domains/immunology , Sequence Deletion , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
13.
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
14.
Nat Commun ; 11(1): 4198, 2020 08 21.
Article in English | MEDLINE | ID: covidwho-724360

ABSTRACT

COVID-19 caused by SARS-CoV-2 has become a global pandemic requiring the development of interventions for the prevention or treatment to curtail mortality and morbidity. No vaccine to boost mucosal immunity, or as a therapeutic, has yet been developed to SARS-CoV-2. In this study, we discover and characterize a cross-reactive human IgA monoclonal antibody, MAb362. MAb362 binds to both SARS-CoV and SARS-CoV-2 spike proteins and competitively blocks ACE2 receptor binding, by overlapping the ACE2 structural binding epitope. Furthermore, MAb362 IgA neutralizes both pseudotyped SARS-CoV and SARS-CoV-2 in 293 cells expressing ACE2. When converted to secretory IgA, MAb326 also neutralizes authentic SARS-CoV-2 virus while the IgG isotype shows no neutralization. Our results suggest that SARS-CoV-2 specific IgA antibodies, such as MAb362, may provide effective immunity against SARS-CoV-2 by inducing mucosal immunity within the respiratory system, a potentially critical feature of an effective vaccine.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Immunoglobulin A/immunology , Peptidyl-Dipeptidase A/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Animals , Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , Chlorocebus aethiops , Cross Reactions , Epitopes , HEK293 Cells , Humans , Immunoglobulin A/metabolism , Immunoglobulin A, Secretory/immunology , Immunoglobulin A, Secretory/metabolism , Immunoglobulin G/immunology , Immunoglobulin G/metabolism , Models, Molecular , Mutation , Protein Binding , Protein Interaction Domains and Motifs , SARS Virus/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vero Cells
15.
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
16.
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
17.
Int J Mol Sci ; 21(16)2020 Aug 13.
Article in English | MEDLINE | ID: covidwho-717745

ABSTRACT

While SARS-CoV-2 uses angiotensin converting enzyme 2 (ACE2) as the receptor for cell entry, it is important to examine other potential interactions between the virus and other cell receptors. Based on the clinical observation of low prevalence of smoking among hospitalized COVID-19 patients, we examined and identified a "toxin-like" amino acid (aa) sequence in the Receptor Binding Domain of the Spike Glycoprotein of SARS-CoV-2 (aa 375-390), which is homologous to a sequence of the Neurotoxin homolog NL1, one of the many snake venom toxins that are known to interact with nicotinic acetylcholine receptors (nAChRs). We present the 3D structural location of this "toxin-like" sequence on the Spike Glycoprotein and the superposition of the modelled structure of the Neurotoxin homolog NL1 and the SARS-CoV-2 Spike Glycoprotein. We also performed computational molecular modelling and docking experiments using 3D structures of the SARS-CoV-2 Spike Glycoprotein and the extracellular domain of the nAChR α9 subunit. We identified a main interaction between the aa 381-386 of the SARS-CoV-2 Spike Glycoprotein and the aa 189-192 of the extracellular domain of the nAChR α9 subunit, a region which forms the core of the "toxin-binding site" of the nAChRs. The mode of interaction is very similar to the interaction between the α9 nAChR and α-bungarotoxin. A similar interaction was observed between the pentameric α7 AChR chimera and SARS-CoV-2 Spike Glycoprotein. The findings raise the possibility that SARS-CoV-2 may interact with nAChRs, supporting the hypothesis of dysregulation of the nicotinic cholinergic system being implicated in the pathophysiology of COVID-19. Nicotine and other nicotinic cholinergic agonists may protect nAChRs and thus have therapeutic value in COVID-19 patients.


Subject(s)
Betacoronavirus/metabolism , Receptors, Nicotinic/genetics , Receptors, Nicotinic/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Sequence/genetics , Computational Biology , Coronavirus Infections/physiopathology , Humans , Molecular Docking Simulation , Neurotoxins/genetics , Neurotoxins/metabolism , Pandemics , Pneumonia, Viral/physiopathology , Protein Structure, Tertiary/genetics , Sequence Alignment , Snake Venoms/genetics
18.
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
19.
Int J Mol Sci ; 21(16)2020 Aug 09.
Article in English | MEDLINE | ID: covidwho-713065

ABSTRACT

The pandemic evolution of SARS-CoV-2 infection is forcing the scientific community to unprecedented efforts to explore all possible approaches against COVID-19. In this context, targeting virus entry is a promising antiviral strategy for controlling viral infections. The main strategies pursued to inhibit the viral entry are considering both the virus and the host factors involved in the process. Primarily, direct-acting antivirals rely on inhibition of the interaction between ACE2 and the receptor binding domain (RBD) of the Spike (S) protein or targeting the more conserved heptad repeats (HRs), involved in the membrane fusion process. The inhibition of host TMPRSS2 and cathepsins B/L may represent a complementary strategy to be investigated. In this review, we discuss the development entry inhibitors targeting the S protein, as well as the most promising host targeting strategies involving TMPRSS2 and CatB/L, which have been exploited so far against CoVs and other related viruses.


Subject(s)
Angiotensin-Converting Enzyme Inhibitors/pharmacology , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Serine Proteinase Inhibitors/pharmacology , Virus Internalization/drug effects , Animals , Betacoronavirus/metabolism , Betacoronavirus/physiology , Humans , Spike Glycoprotein, Coronavirus/metabolism
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