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1.
J Proteome Res ; 19(4): 1351-1360, 2020 04 03.
Article in English | MEDLINE | ID: covidwho-688546

ABSTRACT

As the infection of 2019-nCoV coronavirus is quickly developing into a global pneumonia epidemic, the careful analysis of its transmission and cellular mechanisms is sorely needed. In this Communication, we first analyzed two recent studies that concluded that snakes are the intermediate hosts of 2019-nCoV and that the 2019-nCoV spike protein insertions share a unique similarity to HIV-1. However, the reimplementation of the analyses, built on larger scale data sets using state-of-the-art bioinformatics methods and databases, presents clear evidence that rebuts these conclusions. Next, using metagenomic samples from Manis javanica, we assembled a draft genome of the 2019-nCoV-like coronavirus, which shows 73% coverage and 91% sequence identity to the 2019-nCoV genome. In particular, the alignments of the spike surface glycoprotein receptor binding domain revealed four times more variations in the bat coronavirus RaTG13 than in the Manis coronavirus compared with 2019-nCoV, suggesting the pangolin as a missing link in the transmission of 2019-nCoV from bats to human.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/virology , Genome, Viral/genetics , Host-Pathogen Interactions , Models, Molecular , Pneumonia, Viral/virology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Sequence , Animals , Betacoronavirus/classification , Eutheria/virology , HIV-1/genetics , Humans , Metagenome , Pandemics , Protein Structure, Tertiary , Sequence Alignment , Sequence Analysis, Protein , Snakes/virology
2.
J Med Virol ; 92(6): 584-588, 2020 06.
Article in English | MEDLINE | ID: covidwho-685102

ABSTRACT

Last December 2019, a new virus, named novel Coronavirus (COVID-2019) causing many cases of severe pneumonia was reported in Wuhan, China. The virus knowledge is limited and especially about COVID-2019 pathogenesis. The Open Reading Frame 1ab (ORF1ab) of COVID-2019 has been analyzed to evidence the presence of mutation caused by selective pressure on the virus. For selective pressure analysis fast-unconstrained Bayesian approximation (FUBAR) was used. Homology modelling has been performed by SwissModel and HHPred servers. The presence of transmembrane helical segments in Coronavirus ORF1ab non structural protein 2 (nsp2) and nsp3 was tested by TMHMM, MEMSAT, and MEMPACK tools. Three-dimensional structures have been analyzed and displayed using PyMOL. FUBAR analysis revealed the presence of potential sites under positive selective pressure (P < .05). Position 723 in the COVID-2019 has a serine instead a glycine residue, while at aminoacidic position 1010 a proline instead an isoleucine. Significant (P < .05) pervasive negative selection in 2416 sites (55%) was found. The positive selective pressure could account for some clinical features of this virus compared with severe acute respiratory syndrome (SARS) and Bat SARS-like CoV. The stabilizing mutation falling in the endosome-associated-protein-like domain of the nsp2 protein could account for COVID-2019 high ability of contagious, while the destabilizing mutation in nsp3 proteins could suggest a potential mechanism differentiating COVID-2019 from SARS. These data could be helpful for further investigation aimed to identify potential therapeutic targets or vaccine strategy, especially in the actual moment when the epidemic is ongoing and the scientific community is trying to enrich knowledge about this new viral pathogen.


Subject(s)
Betacoronavirus/genetics , SARS Virus/genetics , Viral Nonstructural Proteins/chemistry , Viral Proteins/chemistry , Betacoronavirus/pathogenicity , Coronavirus Infections/virology , Female , Gene Expression , Humans , Male , Models, Molecular , Mutation , Pandemics , Pneumonia, Viral/virology , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Protein Interaction Domains and Motifs , SARS Virus/pathogenicity , Selection, Genetic , Structural Homology, Protein , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism , Viral Proteins/genetics , Viral Proteins/metabolism
3.
Nat Commun ; 11(1): 3718, 2020 07 24.
Article in English | MEDLINE | ID: covidwho-680541

ABSTRACT

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19 illness, has caused millions of infections worldwide. In SARS coronaviruses, the non-structural protein 16 (nsp16), in conjunction with nsp10, methylates the 5'-end of virally encoded mRNAs to mimic cellular mRNAs, thus protecting the virus from host innate immune restriction. We report here the high-resolution structure of a ternary complex of SARS-CoV-2 nsp16 and nsp10 in the presence of cognate RNA substrate analogue and methyl donor, S-adenosyl methionine (SAM). The nsp16/nsp10 heterodimer is captured in the act of 2'-O methylation of the ribose sugar of the first nucleotide of SARS-CoV-2 mRNA. We observe large conformational changes associated with substrate binding as the enzyme transitions from a binary to a ternary state. This induced fit model provides mechanistic insights into the 2'-O methylation of the viral mRNA cap. We also discover a distant (25 Å) ligand-binding site unique to SARS-CoV-2, which can alternatively be targeted, in addition to RNA cap and SAM pockets, for antiviral development.


Subject(s)
Methyltransferases/chemistry , RNA Caps/metabolism , Viral Regulatory and Accessory Proteins/chemistry , Betacoronavirus , Coronavirus Infections/virology , Humans , Methyltransferases/metabolism , Models, Chemical , Models, Molecular , Pandemics , Pneumonia, Viral/virology , RNA, Viral/metabolism , S-Adenosylmethionine/metabolism , Viral Regulatory and Accessory Proteins/metabolism , X-Ray Diffraction
4.
Nat Commun ; 11(1): 3717, 2020 07 24.
Article in English | MEDLINE | ID: covidwho-680539

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the COVID-19 pandemic. 2'-O-RNA methyltransferase (MTase) is one of the enzymes of this virus that is a potential target for antiviral therapy as it is crucial for RNA cap formation; an essential process for viral RNA stability. This MTase function is associated with the nsp16 protein, which requires a cofactor, nsp10, for its proper activity. Here we show the crystal structure of the nsp10-nsp16 complex bound to the pan-MTase inhibitor sinefungin in the active site. Our structural comparisons reveal low conservation of the MTase catalytic site between Zika and SARS-CoV-2 viruses, but high conservation of the MTase active site between SARS-CoV-2 and SARS-CoV viruses; these data suggest that the preparation of MTase inhibitors targeting several coronaviruses - but not flaviviruses - should be feasible. Together, our data add to important information for structure-based drug discovery.


Subject(s)
Betacoronavirus/enzymology , Methyltransferases/chemistry , Viral Regulatory and Accessory Proteins/chemistry , Adenosine/analogs & derivatives , Adenosine/metabolism , Adenosine/pharmacology , Catalytic Domain , Coronavirus Infections/virology , Crystallography, X-Ray , Enzyme Inhibitors/metabolism , Enzyme Inhibitors/pharmacology , Humans , Methyltransferases/metabolism , Models, Chemical , Models, Molecular , Pandemics , Pneumonia, Viral/virology , RNA Caps , RNA Stability , RNA, Viral/metabolism , Viral Regulatory and Accessory Proteins/metabolism
5.
Viruses ; 12(8)2020 07 26.
Article in English | MEDLINE | ID: covidwho-671037

ABSTRACT

COVID-19 is a pandemic health emergency faced by the entire world. The clinical treatment of the severe acute respiratory syndrome (SARS) CoV-2 is currently based on the experimental administration of HIV antiviral drugs, such as lopinavir, ritonavir, and remdesivir (a nucleotide analogue used for Ebola infection). This work proposes a repurposing process using a database containing approximately 8000 known drugs in synergy structure- and ligand-based studies by means of the molecular docking and descriptor-based protocol. The proposed in silico findings identified new potential SARS CoV-2 main protease (MPRO) inhibitors that fit in the catalytic binding site of SARS CoV-2 MPRO. Several selected structures are NAD-like derivatives, suggesting a relevant role of these molecules in the modulation of SARS CoV-2 infection in conditions of cell chronic oxidative stress. Increased catabolism of NAD(H) during protein ribosylation in the DNA damage repair process may explain the greater susceptibility of the elderly population to the acute respiratory symptoms of COVID-19. The molecular modelling studies proposed herein agree with this hypothesis.


Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Betacoronavirus/enzymology , Coronavirus Infections/drug therapy , Cysteine Endopeptidases/chemistry , NAD/metabolism , Pandemics , Pneumonia, Viral/drug therapy , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/chemistry , Aging/metabolism , Binding Sites , Computer Simulation , Coronavirus Infections/metabolism , Coronavirus Infections/virology , DNA Damage , Drug Repositioning , HIV Protease Inhibitors/chemistry , HIV Protease Inhibitors/pharmacology , Humans , Models, Molecular , Molecular Docking Simulation , Oxidation-Reduction , Pneumonia, Viral/metabolism , Pneumonia, Viral/virology , Protease Inhibitors/chemistry
6.
Nat Commun ; 11(1): 3618, 2020 07 17.
Article in English | MEDLINE | ID: covidwho-651635

ABSTRACT

Global emergencies caused by the severe acute respiratory syndrome coronavirus (SARS-CoV), Middle-East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2 significantly endanger human health. The spike (S) glycoprotein is the key antigen and its conserved S2 subunit contributes to viral entry by mediating host-viral membrane fusion. However, structural information of the post-fusion S2 from these highly pathogenic human-infecting coronaviruses is still lacking. We used single-particle cryo-electron microscopy to show that the post-fusion SARS-CoV S2 forms a further rotated HR1-HR2 six-helix bundle and a tightly bound linker region upstream of the HR2 motif. The structures of pre- and post-fusion SARS-CoV S glycoprotein dramatically differ, resembling that of the Mouse hepatitis virus (MHV) and other class I viral fusion proteins. This structure suggests potential targets for the development of vaccines and therapies against a wide range of SARS-like coronaviruses.


Subject(s)
Betacoronavirus/chemistry , Betacoronavirus/physiology , Spike Glycoprotein, Coronavirus/chemistry , Amino Acid Motifs , Coronavirus/chemistry , Coronavirus/classification , Coronavirus Infections/virology , Cryoelectron Microscopy , Humans , Membrane Fusion , Models, Molecular , Pandemics , Pneumonia, Viral/virology , Protein Conformation , Protein Multimerization , Virus Internalization
7.
Molecules ; 25(14)2020 Jul 13.
Article in English | MEDLINE | ID: covidwho-646769

ABSTRACT

We use state-of-the-art computer-aided drug design (CADD) techniques to identify prospective inhibitors of the main protease enzyme, 3CLpro of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19. From our screening of over one million compounds including approved drugs, investigational drugs, natural products, and organic compounds, and a rescreening protocol incorporating enzyme dynamics via ensemble docking, we have been able to identify a range of prospective 3CLpro inhibitors. Importantly, some of the identified compounds had previously been reported to exhibit inhibitory activities against the 3CLpro enzyme of the closely related SARS-CoV virus. The top-ranking compounds are characterized by the presence of multiple bi- and monocyclic rings, many of them being heterocycles and aromatic, which are flexibly linked allowing the ligands to adapt to the geometry of the 3CLpro substrate site and involve a high amount of functional groups enabling hydrogen bond formation with surrounding amino acid residues, including the catalytic dyad residues H41 and C145. Among the top binding compounds we identified several tyrosine kinase inhibitors, which include a bioflavonoid, the group of natural products that binds best to 3CLpro. Another class of compounds that decently binds to the SARS-CoV-2 main protease are steroid hormones, which thus may be endogenous inhibitors and might provide an explanation for the age-dependent severity of COVID-19. Many of the compounds identified by our work show a considerably stronger binding than found for reference compounds with in vitro demonstrated 3CLpro inhibition and anticoronavirus activity. The compounds determined in this work thus represent a good starting point for the design of inhibitors of SARS-CoV-2 replication.


Subject(s)
Betacoronavirus/enzymology , Coronavirus Infections/drug therapy , Drug Discovery , Pneumonia, Viral/drug therapy , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Binding Sites , Computer Simulation , Cysteine Endopeptidases , Drug Design , Humans , Inhibitory Concentration 50 , Ligands , Models, Molecular , Molecular Structure , Pandemics , Software , Thermodynamics
8.
Microbes Infect ; 22(4-5): 182-187, 2020.
Article in English | MEDLINE | ID: covidwho-626674

ABSTRACT

Envelope protein of coronaviruses is a structural protein existing in both monomeric and homo-pentameric form. It has been related to a multitude of roles including virus infection, replication, dissemination and immune response stimulation. In the present study, we employed an immunoinformatic approach to investigate the major immunogenic domains of the SARS-CoV-2 envelope protein and map them among the homologue proteins of coronaviruses with tropism for animal species that are closely inter-related with the human beings population all over the world. Also, when not available, we predicted the envelope protein structural folding and mapped SARS-CoV-2 epitopes. Envelope sequences alignment provides evidence of high sequence homology for some of the investigated virus specimens; while the structural mapping of epitopes resulted in the interesting maintenance of the structural folding and epitope sequence localization also in the envelope proteins scoring a lower alignment score. In line with the One-Health approach, our evidences provide a molecular structural rationale for a potential role of taxonomically related coronaviruses in conferring protection from SARS-CoV-2 infection and identifying potential candidates for the development of diagnostic tools and prophylactic-oriented strategies.


Subject(s)
Betacoronavirus/metabolism , Computational Biology/methods , Coronavirus Infections/immunology , Coronavirus Infections/virology , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Viral Envelope Proteins/immunology , Animals , Betacoronavirus/classification , Betacoronavirus/genetics , Betacoronavirus/immunology , Epitope Mapping , Gene Expression Regulation, Viral , Humans , Models, Molecular , One Health , Pandemics , Phylogeny , Protein Conformation , Sequence Alignment , Sequence Analysis, Protein
9.
Nat Commun ; 11(1): 3202, 2020 06 24.
Article in English | MEDLINE | ID: covidwho-616613

ABSTRACT

The COVID-19 disease caused by the SARS-CoV-2 coronavirus has become a pandemic health crisis. An attractive target for antiviral inhibitors is the main protease 3CL Mpro due to its essential role in processing the polyproteins translated from viral RNA. Here we report the room temperature X-ray structure of unliganded SARS-CoV-2 3CL Mpro, revealing the ligand-free structure of the active site and the conformation of the catalytic site cavity at near-physiological temperature. Comparison with previously reported low-temperature ligand-free and inhibitor-bound structures suggest that the room temperature structure may provide more relevant information at physiological temperatures for aiding in molecular docking studies.


Subject(s)
Betacoronavirus/enzymology , Cysteine Endopeptidases/chemistry , Viral Nonstructural Proteins/chemistry , Catalytic Domain , Crystallography, X-Ray , Cysteine Endopeptidases/metabolism , Cysteine Proteinase Inhibitors/metabolism , Ligands , Models, Molecular , Molecular Dynamics Simulation , Protein Binding , Protein Conformation , Protein Domains , Protein Structure, Secondary , Temperature , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolism
10.
Biomolecules ; 10(6)2020 Jun 24.
Article in English | MEDLINE | ID: covidwho-613362

ABSTRACT

The pandemic associated with Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV2) and its disease named COVID-19 challenged the scientific community to discover effective therapeutic solutions in a short period. Repurposing existing drugs is one viable approach that emphasizes speed during these urgent times. Famotidine, a class A G protein-coupled receptor antagonist used for the treatment of gastroesophageal reflux was recently identified in an in silico screening. Additionally, a recent retrospective clinical report showed that the treatment with famotidine provided a good outcome in patients infected with SARS-CoV2. A clinical trial testing effectiveness of famotidine in combination with hydroxychloroquine is currently ongoing in the United States (US). In the 1990s, famotidine was described as an antiviral agent against human immunodeficiency virus (HIV). Interestingly, some HIV protease inhibitors are presently being used against SARS-CoV2. However, it is not clear if famotidine could be effective against SARS-CoV2. Thus, by using a computational analysis, we aimed to examine if the antiviral effect of famotidine could be related to the inhibition of proteases involved in the virus replication. Our results showed that famotidine could interact within the catalytic site of the three proteases associated with SARS-CoV2 replication. However, weak binding affinity of famotidine to these proteases suggests that a successful famotidine therapy could likely be achieved only in combination with other antiviral drugs. Finally, analysis of famotidine's pharmacokinetic parameters indicated that its effect against SARS-CoV2 infection could be reached only upon intravenous administration. This work will contribute to the pharmacological knowledge of famotidine as an antiviral agent against SARS-CoV2.


Subject(s)
Antiviral Agents/therapeutic use , Coronavirus Infections/drug therapy , Famotidine/therapeutic use , Pneumonia, Viral/drug therapy , Receptors, G-Protein-Coupled/antagonists & inhibitors , Administration, Intravenous , Antiviral Agents/administration & dosage , Antiviral Agents/pharmacokinetics , Computer Simulation , Drug Repositioning , Famotidine/administration & dosage , Famotidine/pharmacokinetics , Humans , Models, Molecular , Molecular Docking Simulation , Pandemics , Protease Inhibitors/administration & dosage , Protease Inhibitors/pharmacokinetics , Protease Inhibitors/therapeutic use , Virus Replication/drug effects
11.
Biochemistry ; 59(28): 2608-2615, 2020 07 21.
Article in English | MEDLINE | ID: covidwho-612794

ABSTRACT

The virus that causes COVID-19, SARS-CoV-2, has a large RNA genome that encodes numerous proteins that might be targets for antiviral drugs. Some of these proteins, such as the RNA-dependent RNA polymerase, helicase, and main protease, are well conserved between SARS-CoV-2 and the original SARS virus, but several others are not. This study examines one of the proteins encoded by SARS-CoV-2 that is most different, a macrodomain of nonstructural protein 3 (nsp3). Although 26% of the amino acids in this SARS-CoV-2 macrodomain differ from those observed in other coronaviruses, biochemical and structural data reveal that the protein retains the ability to bind ADP-ribose, which is an important characteristic of beta coronaviruses and a potential therapeutic target.


Subject(s)
Betacoronavirus/chemistry , Viral Nonstructural Proteins/chemistry , Adenosine Diphosphate Ribose/metabolism , Coronavirus/chemistry , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Crystallography, X-Ray , Drug Delivery Systems , Humans , Models, Molecular , Pandemics , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , Protein Domains , Thermodynamics , Viral Nonstructural Proteins/metabolism
12.
Nature ; 582(7811): 289-293, 2020 06.
Article in English | MEDLINE | ID: covidwho-608904

ABSTRACT

A new coronavirus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the aetiological agent responsible for the 2019-2020 viral pneumonia outbreak of coronavirus disease 2019 (COVID-19)1-4. Currently, there are no targeted therapeutic agents for the treatment of this disease, and effective treatment options remain very limited. Here we describe the results of a programme that aimed to rapidly discover lead compounds for clinical use, by combining structure-assisted drug design, virtual drug screening and high-throughput screening. This programme focused on identifying drug leads that target main protease (Mpro) of SARS-CoV-2: Mpro is a key enzyme of coronaviruses and has a pivotal role in mediating viral replication and transcription, making it an attractive drug target for SARS-CoV-25,6. We identified a mechanism-based inhibitor (N3) by computer-aided drug design, and then determined the crystal structure of Mpro of SARS-CoV-2 in complex with this compound. Through a combination of structure-based virtual and high-throughput screening, we assayed more than 10,000 compounds-including approved drugs, drug candidates in clinical trials and other pharmacologically active compounds-as inhibitors of Mpro. Six of these compounds inhibited Mpro, showing half-maximal inhibitory concentration values that ranged from 0.67 to 21.4 µM. One of these compounds (ebselen) also exhibited promising antiviral activity in cell-based assays. Our results demonstrate the efficacy of our screening strategy, which can lead to the rapid discovery of drug leads with clinical potential in response to new infectious diseases for which no specific drugs or vaccines are available.


Subject(s)
Betacoronavirus/chemistry , Cysteine Endopeptidases/chemistry , Drug Discovery/methods , Models, Molecular , Protease Inhibitors/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/chemistry , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Cells, Cultured/virology , Coronavirus Infections/enzymology , Coronavirus Infections/virology , Drug Design , Drug Evaluation, Preclinical , Humans , Pandemics , Pneumonia, Viral/enzymology , Pneumonia, Viral/virology , Protease Inhibitors/pharmacology , Protein Structure, Tertiary
13.
Aging (Albany NY) ; 12(12): 11263-11276, 2020 06 16.
Article in English | MEDLINE | ID: covidwho-601536

ABSTRACT

The outbreak of COVID-19 has now become a global pandemic that has severely impacted lives and economic stability. There is, however, no effective antiviral drug that can be used to treat COVID-19 to date. Built on the fact that SARS-CoV-2 initiates its entry into human cells by the receptor binding domain (RBD) of its spike protein binding to the angiotensin-converting enzyme 2 (hACE2), we extended a recently developed approach, EvoDesign, to design multiple peptide sequences that can competitively bind to the SARS-CoV-2 RBD to inhibit the virus from entering human cells. The protocol starts with the construction of a hybrid peptidic scaffold by linking two fragments grafted from the interface of the hACE2 protein (a.a. 22-44 and 351-357) with a linker glycine, which is followed by the redesign and refinement simulations of the peptide sequence to optimize its binding affinity to the interface of the SARS-CoV-2 RBD. The binding experiment analyses showed that the designed peptides exhibited a significantly stronger binding potency to hACE2 than the wild-type hACE2 receptor (with -53.35 vs. -46.46 EvoEF2 energy unit scores for the top designed and wild-type peptides, respectively). This study demonstrates a new avenue to utilize computationally designed peptide motifs to treat the COVID-19 disease by blocking the critical spike-RBD and hACE2 interactions.


Subject(s)
Coronavirus Infections/drug therapy , Peptides/chemical synthesis , Peptides/pharmacology , Peptidyl-Dipeptidase A/physiology , Pneumonia, Viral/drug therapy , Spike Glycoprotein, Coronavirus/physiology , Amino Acid Sequence , Antiviral Agents , Binding Sites , Drug Design , Evolution, Molecular , Humans , Models, Molecular , Pandemics , Protein Binding , Protein Conformation , Virus Internalization/drug effects
15.
J Phys Chem Lett ; 11(14): 5661-5667, 2020 Jul 16.
Article in English | MEDLINE | ID: covidwho-598380

ABSTRACT

Coronaviruses may produce severe acute respiratory syndrome (SARS). As a matter of fact, a new SARS-type virus, SARS-CoV-2, is responsible for the global pandemic in 2020 with unprecedented sanitary and economic consequences for most countries. In the present contribution we study, by all-atom equilibrium and enhanced sampling molecular dynamics simulations, the interaction between the SARS Unique Domain and RNA guanine quadruplexes, a process involved in eluding the defensive response of the host thus favoring viral infection of human cells. Our results evidence two stable binding modes involving an interaction site spanning either the protein dimer interface or only one monomer. The free energy profile unequivocally points to the dimer mode as the thermodynamically favored one. The effect of these binding modes in stabilizing the protein dimer was also assessed, being related to its biological role in assisting the SARS viruses to bypass the host protective response. This work also constitutes a first step in the possible rational design of efficient therapeutic agents aiming at perturbing the interaction between SARS Unique Domain and guanine quadruplexes, hence enhancing the host defenses against the virus.


Subject(s)
Betacoronavirus/chemistry , Betacoronavirus/genetics , Coronavirus Infections/virology , G-Quadruplexes/drug effects , Pneumonia, Viral/virology , RNA, Viral/chemistry , RNA, Viral/genetics , Betacoronavirus/drug effects , Dimerization , Humans , Models, Molecular , Molecular Dynamics Simulation , Pandemics , Protein Binding , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics
17.
Cell Rep ; 31(11): 107774, 2020 06 16.
Article in English | MEDLINE | ID: covidwho-594914

ABSTRACT

The ongoing global pandemic of coronavirus disease 2019 (COVID-19) has caused a huge number of human deaths. Currently, there are no specific drugs or vaccines available for this virus (SARS-CoV-2). The viral polymerase is a promising antiviral target. Here, we describe the near-atomic-resolution structure of the SARS-CoV-2 polymerase complex consisting of the nsp12 catalytic subunit and nsp7-nsp8 cofactors. This structure highly resembles the counterpart of SARS-CoV with conserved motifs for all viral RNA-dependent RNA polymerases and suggests a mechanism of activation by cofactors. Biochemical studies reveal reduced activity of the core polymerase complex and lower thermostability of individual subunits of SARS-CoV-2 compared with SARS-CoV. These findings provide important insights into RNA synthesis by coronavirus polymerase and indicate adaptation of SARS-CoV-2 toward humans with a relatively lower body temperature than the natural bat hosts.


Subject(s)
Betacoronavirus/enzymology , Cryoelectron Microscopy , RNA Replicase/chemistry , Viral Nonstructural Proteins/chemistry , Amino Acid Substitution , Escherichia coli/genetics , Evolution, Molecular , Models, Molecular , Multiprotein Complexes/chemistry , RNA Replicase/metabolism , SARS Virus/enzymology , Viral Nonstructural Proteins/metabolism
18.
Food Funct ; 11(6): 5565-5572, 2020 Jun 24.
Article in English | MEDLINE | ID: covidwho-594573

ABSTRACT

To date, no specific drug has been discovered for the treatment of COVID-19 and hence, people are in a state of anxiety. Thus, there is an urgent need to search for various possible strategies including nutritional supplementation. In this study, we have tried to provide a reference for protein supplementation. Specifically, 20 marine fish proteins were subjected to in silico hydrolysis by gastrointestinal enzymes, and a large number of active peptides were generated. Then, the binding abilities of these peptides to SARS-CoV-2 main protease and monoamine oxidase A were assessed. The results showed that NADH dehydrogenase could be a good protein source in generating potent binders to the two enzymes, followed by cytochrome b. In addition, some high-affinity oligopeptides (VIQY, ICIY, PISQF, VISAW, AIPAW, and PVSQF) were identified as dual binders to the two enzymes. In summary, the supplementation of some fish proteins can be helpful for COVID-19 patients; the identified oligopeptides can be used as the lead compounds to design potential inhibitors against COVID-19 and anxiety.


Subject(s)
Antiviral Agents/metabolism , Betacoronavirus/metabolism , Coronavirus Infections/virology , Dietary Supplements , Fish Proteins/metabolism , Monoamine Oxidase/metabolism , Pneumonia, Viral/virology , Animals , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Aquatic Organisms , Betacoronavirus/enzymology , Coronavirus Infections/drug therapy , Decapodiformes/metabolism , Fish Proteins/chemistry , Fish Proteins/therapeutic use , Fishes/metabolism , Models, Molecular , Molecular Docking Simulation , Monoamine Oxidase Inhibitors , Pandemics , Perciformes/metabolism , Pneumonia, Viral/drug therapy , Protein Binding , Protein Conformation , Salmon/metabolism , Tuna/metabolism
19.
J Struct Biol ; 211(2): 107548, 2020 08 01.
Article in English | MEDLINE | ID: covidwho-593332

ABSTRACT

We report the crystal structure of the SARS-CoV-2 putative primase composed of the nsp7 and nsp8 proteins. We observed a dimer of dimers (2:2 nsp7-nsp8) in the crystallographic asymmetric unit. The structure revealed a fold with a helical core of the heterotetramer formed by both nsp7 and nsp8 that is flanked with two symmetry-related nsp8 ß-sheet subdomains. It was also revealed that two hydrophobic interfaces one of approx. 1340 Å2 connects the nsp7 to nsp8 and a second one of approx. 950 Å2 connects the dimers and form the observed heterotetramer. Interestingly, analysis of the surface electrostatic potential revealed a putative RNA binding site that is formed only within the heterotetramer.


Subject(s)
Betacoronavirus/chemistry , DNA Primase/chemistry , Viral Nonstructural Proteins/chemistry , Binding Sites , Crystallography, X-Ray , DNA Primase/metabolism , Models, Molecular , Multiprotein Complexes , Protein Conformation , Protein Multimerization , RNA/metabolism , Viral Nonstructural Proteins/metabolism
20.
Vaccine ; 38(32): 5071-5075, 2020 07 06.
Article in English | MEDLINE | ID: covidwho-592568

ABSTRACT

SARS-CoV-2 is the cause of the worldwide outbreak of COVID-19 that has been characterized as a pandemic by the WHO. Since the first report of COVID-19 on December 31, 2019, 179,111 cases were confirmed in 160 countries/regions with 7426 deaths as of March 17, 2020. However, there have been no vaccines approved in the world to date. In this study, we analyzed the biological characteristics of the SARS-CoV-2 Spike protein, Pro330-Leu650 (SARS-CoV-2-SPL), using biostatistical methods. SARS-CoV-2-SPL possesses a receptor-binding region (RBD) and important B (Ser438-Gln506, Thr553-Glu583, Gly404-Aps427, Thr345-Ala352, and Lys529-Lys535) and T (9 CD4 and 11 CD8 T cell antigenic determinants) cell epitopes. High homology in this region between SARS-CoV-2 and SARS-CoV amounted to 87.7%, after taking the biological similarity of the amino acids into account and eliminating the receptor-binding motif (RBM). The overall topology indicated that the complete structure of SARS-CoV-2-SPL was with RBM as the head, and RBD as the trunk and the tail region. SARS-CoV-2-SPL was found to have the potential to elicit effective B and T cell responses. Our findings may provide meaningful guidance for SARS-CoV-2 vaccine design.


Subject(s)
Betacoronavirus/chemistry , Drug Design , Models, Immunological , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Viral Vaccines/chemistry , Viral Vaccines/immunology , Amino Acid Sequence , Antigens, Viral/chemistry , Antigens, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/epidemiology , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/immunology , Humans , Models, Molecular , Pandemics/prevention & control , Pneumonia, Viral/epidemiology , Pneumonia, Viral/immunology , Pneumonia, Viral/prevention & control , Pneumonia, Viral/virology , Sequence Alignment , Vaccines, Subunit/chemistry , Vaccines, Subunit/immunology
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