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1.
J Med Chem ; 64(8): 4991-5000, 2021 04 22.
Article in English | MEDLINE | ID: covidwho-1574766

ABSTRACT

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


Subject(s)
Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/chemistry , Oligopeptides/chemistry , Binding Sites , Coronavirus 3C Proteases/metabolism , Crystallography/methods , Crystallography, X-Ray , Cysteine Proteinase Inhibitors/chemistry , Cysteine Proteinase Inhibitors/metabolism , Models, Molecular , Neutrons , Oligopeptides/metabolism , Protein Conformation , Protons
2.
Clin Immunol ; 215: 108426, 2020 06.
Article in English | MEDLINE | ID: covidwho-1385285
3.
Int J Mol Sci ; 22(17)2021 Aug 30.
Article in English | MEDLINE | ID: covidwho-1379977

ABSTRACT

A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been identified as the pathogen responsible for the outbreak of a severe, rapidly developing pneumonia (Coronavirus disease 2019, COVID-19). The virus enzyme, called 3CLpro or main protease (Mpro), is essential for viral replication, making it a most promising target for antiviral drug development. Recently, we adopted the drug repurposing as appropriate strategy to give fast response to global COVID-19 epidemic, by demonstrating that the zonulin octapeptide inhibitor AT1001 (Larazotide acetate) binds Mpro catalytic domain. Thus, in the present study we tried to investigate the antiviral activity of AT1001, along with five derivatives, by cell-based assays. Our results provide with the identification of AT1001 peptide molecular framework for lead optimization step to develop new generations of antiviral agents of SARS-CoV-2 with an improved biological activity, expanding the chance for success in clinical trials.


Subject(s)
Antiviral Agents/pharmacology , Molecular Docking Simulation , Oligopeptides/chemistry , Peptides/metabolism , SARS-CoV-2/drug effects , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/therapeutic use , Binding Sites , COVID-19/drug therapy , COVID-19/virology , Catalytic Domain , Cell Line , Cytomegalovirus/drug effects , Drug Repositioning , Herpesvirus 3, Human/drug effects , Humans , Molecular Dynamics Simulation , Peptides/chemical synthesis , Peptides/pharmacology , Peptides/therapeutic use , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Viral Matrix Proteins/chemistry , Viral Matrix Proteins/metabolism
4.
Int J Mol Sci ; 21(20)2020 Oct 16.
Article in English | MEDLINE | ID: covidwho-1298153

ABSTRACT

The non-structural protein 2 (nsP2) of alphavirus Venezuelan equine encephalitis virus (VEEV) is a cysteine protease that is responsible for processing of the viral non-structural polyprotein and is an important drug target owing to the clinical relevance of VEEV. In this study we designed two recombinant VEEV nsP2 constructs to study the effects of an N-terminal extension on the protease activity and to investigate the specificity of the elongated enzyme in vitro. The N-terminal extension was found to have no substantial effect on the protease activity. The amino acid preferences of the VEEV nsP2 protease were investigated on substrates representing wild-type and P5, P4, P2, P1, P1', and P2' variants of Semliki forest virus nsP1/nsP2 cleavage site, using a His6-MBP-mEYFP recombinant substrate-based protease assay which has been adapted for a 96-well plate-based format. The structural basis of enzyme specificity was also investigated in silico by analyzing a modeled structure of VEEV nsP2 complexed with oligopeptide substrate. To our knowledge, in vitro screening of P1' amino acid preferences of VEEV nsP2 protease remains undetermined to date, thus, our results may provide valuable information for studies and inhibitor design of different alphaviruses or other Group IV viruses.


Subject(s)
Encephalitis Virus, Venezuelan Equine/enzymology , Viral Proteases/chemistry , Catalytic Domain , Molecular Dynamics Simulation , Oligopeptides/chemistry , Oligopeptides/metabolism , Substrate Specificity , Viral Proteases/genetics , Viral Proteases/metabolism
5.
Sci Rep ; 11(1): 13208, 2021 06 24.
Article in English | MEDLINE | ID: covidwho-1281733

ABSTRACT

Effective agents to treat coronavirus infection are urgently required, not only to treat COVID-19, but to prepare for future outbreaks. Repurposed anti-virals such as remdesivir and human anti-inflammatories such as barcitinib have received emergency approval but their overall benefits remain unclear. Vaccines are the most promising prospect for COVID-19, but will need to be redeveloped for any future coronavirus outbreak. Protecting against future outbreaks requires the identification of targets that are conserved between coronavirus strains and amenable to drug discovery. Two such targets are the main protease (Mpro) and the papain-like protease (PLpro) which are essential for the coronavirus replication cycle. We describe the discovery of two non-antiviral therapeutic agents, the caspase-1 inhibitor SDZ 224015 and Tarloxotinib that target Mpro and PLpro, respectively. These were identified through extensive experimental screens of the drug repurposing ReFRAME library of 12,000 therapeutic agents. The caspase-1 inhibitor SDZ 224015, was found to be a potent irreversible inhibitor of Mpro (IC50 30 nM) while Tarloxotinib, a clinical stage epidermal growth factor receptor inhibitor, is a sub micromolar inhibitor of PLpro (IC50 300 nM, Ki 200 nM) and is the first reported PLpro inhibitor with drug-like properties. SDZ 224015 and Tarloxotinib have both undergone safety evaluation in humans and hence are candidates for COVID-19 clinical evaluation.


Subject(s)
Antiviral Agents/chemistry , COVID-19/drug therapy , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus Papain-Like Proteases/antagonists & inhibitors , Drug Repositioning , Oligopeptides/chemistry , Cell Line , Humans , Serpins/chemistry , Viral Proteins/chemistry
6.
Biomed Pharmacother ; 141: 111722, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1252499

ABSTRACT

Coronavirus disease 2019 is associated with clinical symptoms including severe inflammatory syndrome and a higher expression of angiotensin II. As a pro-inflammatory mediator, the physiologic effects of angiotensin II are mediated by a G-protein coupled receptor, termed AT1R. Following binding, AT1R initiates the process of signal desensitization necessary to maintain cellular homeostasis. At the cellular level, this function occurs via the G protein-dependent signaling and the phosphorylation. We describe amino acids similarities between SARS COV-2 nonstructural protein (NSP8) which is associated with intracellular membranes and AT1R key sites. Since abnormal activation of AT1R receptor leads to a number of physiological disorders, we hypothesize that SARS COV-2 might further interfere with the angiotensin II receptor functions.


Subject(s)
Coronavirus RNA-Dependent RNA Polymerase/genetics , Oligopeptides/genetics , Receptor, Angiotensin, Type 1/genetics , SARS-CoV-2/genetics , Viral Nonstructural Proteins/genetics , Amino Acid Sequence , COVID-19/genetics , Coronavirus RNA-Dependent RNA Polymerase/chemistry , Humans , Oligopeptides/chemistry , Receptor, Angiotensin, Type 1/chemistry , SARS-CoV-2/chemistry , Viral Nonstructural Proteins/chemistry
7.
Biochem Biophys Res Commun ; 555: 147-153, 2021 05 28.
Article in English | MEDLINE | ID: covidwho-1157143

ABSTRACT

Several existing drugs are currently being tested worldwide to treat COVID-19 patients. Recent data indicate that SARS-CoV-2 is rapidly evolving into more transmissible variants. It is therefore highly possible that SARS-CoV-2 can accumulate adaptive mutations modulating drug susceptibility and hampering viral antigenicity. Thus, it is vital to predict potential non-synonymous mutation sites and predict the evolution of protein structural modifications leading to drug tolerance. As two FDA-approved anti-hepatitis C virus (HCV) drugs, boceprevir, and telaprevir, have been shown to effectively inhibit SARS-CoV-2 by targeting the main protease (Mpro), here we used a high-throughput interface-based protein design strategy to identify mutational hotspots and potential signatures of adaptation in these drug binding sites of Mpro. Several mutants exhibited reduced binding affinity to these drugs, out of which hotspot residues having a strong tendency to undergo positive selection were identified. The data further indicated that these anti-HCV drugs have larger footprints in the mutational landscape of Mpro and hence encompass the highest potential for positive selection and adaptation. These findings are crucial in understanding the potential structural modifications in the drug binding sites of Mpro and thus its signatures of adaptation. Furthermore, the data could provide systemic strategies for robust antiviral design and discovery against COVID-19 in the future.


Subject(s)
Adaptation, Physiological/genetics , Antiviral Agents/chemistry , Coronavirus 3C Proteases/chemistry , Drug Design , Drug Resistance, Viral/genetics , Mutation , SARS-CoV-2/enzymology , SARS-CoV-2/genetics , Amino Acid Sequence , Antiviral Agents/pharmacology , Binding Sites/drug effects , Binding Sites/genetics , COVID-19/drug therapy , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/genetics , Coronavirus 3C Proteases/metabolism , Genetic Fitness/genetics , Hepacivirus/drug effects , Hepacivirus/enzymology , Ligands , Models, Molecular , Oligopeptides/chemistry , Oligopeptides/pharmacology , Proline/analogs & derivatives , Proline/chemistry , Proline/pharmacology , Reproducibility of Results , SARS-CoV-2/drug effects , Selection, Genetic/genetics , Structure-Activity Relationship
8.
J Chem Inf Model ; 60(12): 5803-5814, 2020 12 28.
Article in English | MEDLINE | ID: covidwho-1065781

ABSTRACT

The main protease (Mpro) of the SARS-CoV-2 virus is one focus of drug development efforts for COVID-19. Here, we show that interactive molecular dynamics in virtual reality (iMD-VR) is a useful and effective tool for creating Mpro complexes. We make these tools and models freely available. iMD-VR provides an immersive environment in which users can interact with MD simulations and so build protein complexes in a physically rigorous and flexible way. Recently, we have demonstrated that iMD-VR is an effective method for interactive, flexible docking of small molecule drugs into their protein targets (Deeks et al. PLoS One 2020, 15, e0228461). Here, we apply this approach to both an Mpro inhibitor and an oligopeptide substrate, using experimentally determined crystal structures. For the oligopeptide, we test against a crystallographic structure of the original SARS Mpro. Docking with iMD-VR gives models in agreement with experimentally observed (crystal) structures. The docked structures are also tested in MD simulations and found to be stable. Different protocols for iMD-VR docking are explored, e.g., with and without restraints on protein backbone, and we provide recommendations for its use. We find that it is important for the user to focus on forming binding interactions, such as hydrogen bonds, and not to rely on using simple metrics (such as RMSD), in order to create realistic, stable complexes. We also test the use of apo (uncomplexed) crystal structures for docking and find that they can give good results. This is because of the flexibility and dynamic response allowed by the physically rigorous, atomically detailed simulation approach of iMD-VR. We make our models (and interactive simulations) freely available. The software framework that we use, Narupa, is open source, and uses commodity VR hardware, so these tools are readily accessible to the wider research community working on Mpro (and other COVID-19 targets). These should be widely useful in drug development, in education applications, e.g., on viral enzyme structure and function, and in scientific communication more generally.


Subject(s)
Antiviral Agents/chemistry , Benzeneacetamides/chemistry , COVID-19/metabolism , Coronavirus 3C Proteases/metabolism , Imidazoles/chemistry , SARS-CoV-2/enzymology , Viral Protease Inhibitors/chemistry , Antiviral Agents/pharmacokinetics , Antiviral Agents/pharmacology , Benzeneacetamides/pharmacokinetics , Benzeneacetamides/pharmacology , Coronavirus 3C Proteases/genetics , Crystallization , Cyclohexylamines , Drug Design , Humans , Hydrogen Bonding , Imidazoles/pharmacokinetics , Imidazoles/pharmacology , Molecular Docking Simulation , Molecular Dynamics Simulation , Mutation , Oligopeptides/chemistry , Oligopeptides/metabolism , Protein Conformation , Pyridines , Structure-Activity Relationship , Viral Protease Inhibitors/pharmacokinetics , Viral Protease Inhibitors/pharmacology
9.
Sci Signal ; 14(665)2021 01 12.
Article in English | MEDLINE | ID: covidwho-1029425

ABSTRACT

The first reported receptor for SARS-CoV-2 on host cells was the angiotensin-converting enzyme 2 (ACE2). However, the viral spike protein also has an RGD motif, suggesting that cell surface integrins may be co-receptors. We examined the sequences of ACE2 and integrins with the Eukaryotic Linear Motif (ELM) resource and identified candidate short linear motifs (SLiMs) in their short, unstructured, cytosolic tails with potential roles in endocytosis, membrane dynamics, autophagy, cytoskeleton, and cell signaling. These SLiM candidates are highly conserved in vertebrates and may interact with the µ2 subunit of the endocytosis-associated AP2 adaptor complex, as well as with various protein domains (namely, I-BAR, LC3, PDZ, PTB, and SH2) found in human signaling and regulatory proteins. Several motifs overlap in the tail sequences, suggesting that they may act as molecular switches, such as in response to tyrosine phosphorylation status. Candidate LC3-interacting region (LIR) motifs are present in the tails of integrin ß3 and ACE2, suggesting that these proteins could directly recruit autophagy components. Our findings identify several molecular links and testable hypotheses that could uncover mechanisms of SARS-CoV-2 attachment, entry, and replication against which it may be possible to develop host-directed therapies that dampen viral infection and disease progression. Several of these SLiMs have now been validated to mediate the predicted peptide interactions.


Subject(s)
COVID-19/virology , Host Microbial Interactions/physiology , SARS-CoV-2/physiology , SARS-CoV-2/pathogenicity , Virus Internalization , Amino Acid Sequence , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/physiology , Animals , COVID-19/therapy , Conserved Sequence , Host Microbial Interactions/genetics , Humans , Integrins/chemistry , Integrins/genetics , Integrins/physiology , Intrinsically Disordered Proteins/chemistry , Intrinsically Disordered Proteins/genetics , Intrinsically Disordered Proteins/physiology , Models, Biological , Models, Molecular , Oligopeptides/chemistry , Oligopeptides/genetics , Oligopeptides/physiology , Protein Interaction Domains and Motifs/genetics , Protein Interaction Domains and Motifs/physiology , Protein Sorting Signals/genetics , Protein Sorting Signals/physiology , Receptors, Virus/chemistry , Receptors, Virus/genetics , Receptors, Virus/physiology , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/physiology
10.
Nanomedicine ; 33: 102351, 2021 04.
Article in English | MEDLINE | ID: covidwho-1009771

ABSTRACT

Acute respiratory distress syndrome (ARDS) is a deadly respiratory illness associated with refractory hypoxemia and pulmonary edema. The recent pandemic outbreak of COVID-19 is associated with severe pneumonia and inflammatory cytokine storm in the lungs. The anti-inflammatory phytomedicine nimbolide (NIM) may not be feasible for clinical translation due to poor pharmacokinetic properties and lack of suitable delivery systems. To overcome these barriers, we have developed nimbolide liposomes conjugated with iRGD peptide (iRGD-NIMLip) for targeting lung inflammation. It was observed that iRGD-NIMLip treatment significantly inhibited oxidative stress and cytokine storm compared to nimbolide free-drug (f-NIM), nimbolide liposomes (NIMLip), and exhibited superior activity compared to dexamethasone (DEX). iRGD-NIMLip abrogated the LPS induced p65 NF-κB, Akt, MAPK, Integrin ß3 and ß5, STAT3, and DNMT1 expression. Collectively, our results demonstrate that iRGD-NIMLip could be a promising novel drug delivery system to target severe pathological consequences observed in ARDS and COVID-19 associated cytokine storm.


Subject(s)
Anti-Inflammatory Agents/administration & dosage , Limonins/administration & dosage , Liposomes/chemistry , Oligopeptides/chemistry , Respiratory Distress Syndrome/drug therapy , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/therapeutic use , Cell Line , Drug Delivery Systems , Endotoxins , Humans , Limonins/chemistry , Limonins/therapeutic use , Lung/drug effects , Lung/pathology , Male , Mice , Mice, Inbred C57BL , RAW 264.7 Cells , Respiratory Distress Syndrome/chemically induced , Respiratory Distress Syndrome/pathology
11.
Comput Biol Med ; 130: 104186, 2021 03.
Article in English | MEDLINE | ID: covidwho-987395

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused over 1.4 million deaths worldwide. Repurposing existing drugs offers the fastest opportunity to identify new indications for existing drugs as a stable solution against coronavirus disease 2019 (COVID-19). The SARS-CoV-2 main protease (Mpro) is a critical target for designing potent antiviral agents against COVID-19. In this study, we identify potential inhibitors against COVID-19, using an amalgam of virtual screening, molecular dynamics (MD) simulations, and binding-free energy approaches from the Korea Chemical Bank drug repurposing (KCB-DR) database. The database screening of KCB-DR resulted in 149 binders. The dynamics of protein-drug complex formation for the seven top scoring drugs were investigated through MD simulations. Six drugs showed stable binding with active site of SARS-CoV-2 Mpro indicated by steady RMSD of protein backbone atoms and potential energy profiles. Furthermore, binding free energy calculations suggested the community-acquired bacterial pneumonia drug ceftaroline fosamil and the hepatitis C virus (HCV) protease inhibitor telaprevir are potent inhibitors against Mpro. Molecular dynamics and interaction analysis revealed that ceftaroline fosamil and telaprevir form hydrogen bonds with important active site residues such as Thr24, Thr25, His41, Thr45, Gly143, Ser144, Cys145, and Glu166 that is supported by crystallographic information of known inhibitors. Telaprevir has potential side effects, but its derivatives have good pharmacokinetic properties and are suggested to bind Mpro. We suggest the telaprevir derivatives and ceftaroline fosamil bind tightly with SARS-CoV-2 Mpro and should be validated through preclinical testing.


Subject(s)
COVID-19/drug therapy , COVID-19/enzymology , Cephalosporins/chemistry , Coronavirus 3C Proteases , Drug Repositioning , Hepacivirus/enzymology , Hepatitis C/drug therapy , Molecular Dynamics Simulation , Oligopeptides/chemistry , SARS-CoV-2 , Cephalosporins/therapeutic use , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/chemistry , Hepatitis C/enzymology , Humans , Oligopeptides/therapeutic use , SARS-CoV-2/chemistry , SARS-CoV-2/enzymology
12.
Immunobiology ; 226(1): 152021, 2021 01.
Article in English | MEDLINE | ID: covidwho-908903

ABSTRACT

SARS-CoV-2 is a highly contagious virus that has caused serious health crisis world-wide resulting into a pandemic situation. As per the literature, the SARS-CoV-2 is known to exploit humanACE2 receptors (similar toprevious SARS-CoV-1) for gaining entry into the host cell for invasion, infection, multiplication and pathogenesis. However, considering the higher infectivity of SARS-CoV-2 along with the complex etiology and pathophysiological outcomes seen in COVID-19 patients, it seems that there may be an alternate receptor for SARS-CoV-2. I performed comparative protein sequence analysis, database based gene expression profiling, bioinformatics based molecular docking using authentic tools and techniques for unveiling the molecular basis of high infectivity of SARS-CoV-2 as compared to previous known coronaviruses. My study revealed that SARS-CoV-2 (previously known as 2019-nCoV) harbors a RGD motif in its receptor binding domain (RBD) and the motif is absent in all other previously known SARS-CoVs. The RGD motif is well known for its role in cell-attachment and cell-adhesion. My hypothesis is that the SARS-CoV-2 may be (via RGD) exploiting integrins, that have high expression in lungs and all other vital organs, for invading host cells. However, an experimental verification is required. The expression of ACE2, which is a known receptor for SARS-CoV-2, was found to be negligible in lungs. I assume that higher infectivity of SARS-CoV-2 could be due to this RGD-integrin mediated acquired cell-adhesive property. Gene expression profiling revealed that expression of integrins is significantly high in lung cells, in particular αvß6, α5ß1, αvß8 and an ECM protein, ICAM1. The molecular docking experiment showed the RBD of spike protein binds with integrins precisely at RGD motif in a similar manner as a synthetic RGD peptide binds to integrins as found by other researchers. SARS-CoV-2 spike protein has a number of phosphorylation sites that can induce cAMP, PKC, Tyr signaling pathways. These pathways either activate calcium ion channels or get activated by calcium. In fact, integrins have calcium & metal binding sites that were predicted around and in vicinity of RGD-integrin docking site in our analysis which suggests that RGD-integrins interaction possibly occurs in calcium-dependent manner. The higher expression of integrins in lungs along with their previously known high binding affinity (~KD = 4.0 nM) for virus RGD motif could serve as a possible explanation for high infectivity of SARS-CoV-2. On the contrary, human ACE2 has lower expression in lungs and its high binding affinity (~KD = 15 nM) for spike RBD alone could not manifest significant virus-host attachment. This suggests that besides human ACE2, an additional or alternate receptor for SARS-CoV-2 is likely to exist. A highly relevant evidence never reported earlier which corroborate in favor of RGD-integrins mediated virus-host attachment is an unleashed cytokine storm which causes due to activation of TNF-α and IL-6 activation; and integrins role in their activation is also well established. Altogether, the current study has highlighted possible role of calcium and other divalent ions in RGD-integrins interaction for virus invasion into host cells and suggested that lowering divalent ion in lungs could avert virus-host cells attachment.


Subject(s)
COVID-19/virology , Calcium/metabolism , Chelation Therapy , Edetic Acid/therapeutic use , Integrins/metabolism , Receptors, Immunologic/metabolism , Receptors, Peptide/metabolism , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Binding Sites/genetics , COVID-19/drug therapy , Calcium Channels/metabolism , Gene Expression Profiling , Humans , Integrins/chemistry , Intercellular Adhesion Molecule-1/metabolism , Interleukin-6/metabolism , Lung/metabolism , Molecular Docking Simulation , Oligopeptides/chemistry , Oligopeptides/metabolism , Protein Binding , Receptors, Virus/metabolism , SARS-CoV-2/metabolism , Sequence Alignment , Signal Transduction/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Tumor Necrosis Factor-alpha/metabolism , Virus Attachment
13.
Sci Rep ; 10(1): 17716, 2020 10 19.
Article in English | MEDLINE | ID: covidwho-880701

ABSTRACT

In the rapidly evolving coronavirus disease (COVID-19) pandemic, repurposing existing drugs and evaluating commercially available inhibitors against druggable targets of the virus could be an effective strategy to accelerate the drug discovery process. The 3C-Like proteinase (3CLpro) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as an important drug target due to its role in viral replication. The lack of a potent 3CLpro inhibitor and the availability of the X-ray crystal structure of 3CLpro (PDB-ID 6LU7) motivated us to perform computational studies to identify commercially available potential inhibitors. A combination of modeling studies was performed to identify potential 3CLpro inhibitors from the protease inhibitor database MEROPS ( https://www.ebi.ac.uk/merops/index.shtml ). Binding energy evaluation identified key residues for inhibitor design. We found 15 potential 3CLpro inhibitors with higher binding affinity than that of an α-ketoamide inhibitor determined via X-ray structure. Among them, saquinavir and three other investigational drugs aclarubicin, TMC-310911, and faldaprevir could be suggested as potential 3CLpro inhibitors. We recommend further experimental investigation of these compounds.


Subject(s)
Betacoronavirus/enzymology , Molecular Docking Simulation , Molecular Dynamics Simulation , Protease Inhibitors/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Aclarubicin/chemistry , Aclarubicin/metabolism , Aminoisobutyric Acids , Betacoronavirus/isolation & purification , Binding Sites , COVID-19 , Coronavirus 3C Proteases , Coronavirus Infections/pathology , Coronavirus Infections/virology , Cysteine Endopeptidases/metabolism , Databases, Factual , Humans , Hydrogen Bonding , Leucine/analogs & derivatives , Oligopeptides/chemistry , Oligopeptides/metabolism , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Proline/analogs & derivatives , Protease Inhibitors/metabolism , Quinolines , SARS-CoV-2 , Thermodynamics , Thiazoles/chemistry , Thiazoles/metabolism , Viral Nonstructural Proteins/metabolism
14.
Sci Adv ; 6(42)2020 10.
Article in English | MEDLINE | ID: covidwho-873433

ABSTRACT

Viral papain-like cysteine protease (PLpro, NSP3) is essential for SARS-CoV-2 replication and represents a promising target for the development of antiviral drugs. Here, we used a combinatorial substrate library and performed comprehensive activity profiling of SARS-CoV-2 PLpro. On the scaffold of the best hits from positional scanning, we designed optimal fluorogenic substrates and irreversible inhibitors with a high degree of selectivity for SARS PLpro. We determined crystal structures of two of these inhibitors in complex with SARS-CoV-2 PLpro that reveals their inhibitory mechanisms and provides a molecular basis for the observed substrate specificity profiles. Last, we demonstrate that SARS-CoV-2 PLpro harbors deISGylating activity similar to SARSCoV-1 PLpro but its ability to hydrolyze K48-linked Ub chains is diminished, which our sequence and structure analysis provides a basis for. Together, this work has revealed the molecular rules governing PLpro substrate specificity and provides a framework for development of inhibitors with potential therapeutic value or drug repurposing.


Subject(s)
Betacoronavirus/enzymology , Drug Design , Protease Inhibitors/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Amino Acid Sequence , Betacoronavirus/isolation & purification , Binding Sites , COVID-19 , Catalytic Domain , Coronavirus 3C Proteases , Coronavirus Infections/pathology , Coronavirus Infections/virology , Crystallography, X-Ray , Cysteine Endopeptidases/genetics , Cysteine Endopeptidases/metabolism , Humans , Kinetics , Molecular Dynamics Simulation , Oligopeptides/chemistry , Oligopeptides/metabolism , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Protease Inhibitors/metabolism , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , SARS-CoV-2 , Substrate Specificity , Ubiquitins/metabolism , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolism
15.
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 , Angiotensin-Converting Enzyme 2 , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Betacoronavirus/chemistry , Betacoronavirus/genetics , Binding Sites/genetics , COVID-19 , 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 , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Virus Internalization
16.
Interdiscip Sci ; 12(3): 368-376, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-459220

ABSTRACT

A novel coronavirus, called 2019-nCoV, was recently found in Wuhan, Hubei Province of China, and now is spreading across China and other parts of the world. Although there are some drugs to treat 2019-nCoV, there is no proper scientific evidence about its activity on the virus. It is of high significance to develop a drug that can combat the virus effectively to save valuable human lives. It usually takes a much longer time to develop a drug using traditional methods. For 2019-nCoV, it is now better to rely on some alternative methods such as deep learning to develop drugs that can combat such a disease effectively since 2019-nCoV is highly homologous to SARS-CoV. In the present work, we first collected virus RNA sequences of 18 patients reported to have 2019-nCoV from the public domain database, translated the RNA into protein sequences, and performed multiple sequence alignment. After a careful literature survey and sequence analysis, 3C-like protease is considered to be a major therapeutic target and we built a protein 3D model of 3C-like protease using homology modeling. Relying on the structural model, we used a pipeline to perform large scale virtual screening by using a deep learning based method to accurately rank/identify protein-ligand interacting pairs developed recently in our group. Our model identified potential drugs for 2019-nCoV 3C-like protease by performing drug screening against four chemical compound databases (Chimdiv, Targetmol-Approved_Drug_Library, Targetmol-Natural_Compound_Library, and Targetmol-Bioactive_Compound_Library) and a database of tripeptides. Through this paper, we provided the list of possible chemical ligands (Meglumine, Vidarabine, Adenosine, D-Sorbitol, D-Mannitol, Sodium_gluconate, Ganciclovir and Chlorobutanol) and peptide drugs (combination of isoleucine, lysine and proline) from the databases to guide the experimental scientists and validate the molecules which can combat the virus in a shorter time.


Subject(s)
Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Deep Learning , Drug Evaluation, Preclinical/methods , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , Viral Nonstructural Proteins/antagonists & inhibitors , Amino Acid Sequence , Antiviral Agents/chemistry , Betacoronavirus/genetics , COVID-19 , Catalytic Domain , Coronavirus 3C Proteases , Coronavirus Infections/epidemiology , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/genetics , Databases, Nucleic Acid , Databases, Pharmaceutical , Drug Design , Drug Evaluation, Preclinical/statistics & numerical data , Humans , Ligands , Models, Molecular , Molecular Dynamics Simulation , Oligopeptides/chemistry , Oligopeptides/pharmacology , Pandemics , Pneumonia, Viral/epidemiology , SARS-CoV-2 , Sequence Alignment , Structural Homology, Protein , User-Computer Interface , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/genetics
17.
J Chem Inf Model ; 60(6): 3277-3286, 2020 06 22.
Article in English | MEDLINE | ID: covidwho-97464

ABSTRACT

The recent outbreak of novel coronavirus disease-19 (COVID-19) calls for and welcomes possible treatment strategies using drugs on the market. It is very efficient to apply computer-aided drug design techniques to quickly identify promising drug repurposing candidates, especially after the detailed 3D structures of key viral proteins are resolved. The virus causing COVID-19 is SARS-CoV-2. Taking advantage of a recently released crystal structure of SARS-CoV-2 main protease in complex with a covalently bonded inhibitor, N3 (Liu et al., 10.2210/pdb6LU7/pdb), I conducted virtual docking screening of approved drugs and drug candidates in clinical trials. For the top docking hits, I then performed molecular dynamics simulations followed by binding free energy calculations using an end point method called MM-PBSA-WSAS (molecular mechanics/Poisson-Boltzmann surface area/weighted solvent-accessible surface area; Wang, Chem. Rev. 2019, 119, 9478; Wang, Curr. Comput.-Aided Drug Des. 2006, 2, 287; Wang; ; Hou J. Chem. Inf. Model., 2012, 52, 1199). Several promising known drugs stand out as potential inhibitors of SARS-CoV-2 main protease, including carfilzomib, eravacycline, valrubicin, lopinavir, and elbasvir. Carfilzomib, an approved anticancer drug acting as a proteasome inhibitor, has the best MM-PBSA-WSAS binding free energy, -13.8 kcal/mol. The second-best repurposing drug candidate, eravacycline, is synthetic halogenated tetracycline class antibiotic. Streptomycin, another antibiotic and a charged molecule, also demonstrates some inhibitory effect, even though the predicted binding free energy of the charged form (-3.8 kcal/mol) is not nearly as low as that of the neutral form (-7.9 kcal/mol). One bioactive, PubChem 23727975, has a binding free energy of -12.9 kcal/mol. Detailed receptor-ligand interactions were analyzed and hot spots for the receptor-ligand binding were identified. I found that one hot spot residue, His41, is a conserved residue across many viruses including SARS-CoV, SARS-CoV-2, MERS-CoV, and hepatitis C virus (HCV). The findings of this study can facilitate rational drug design targeting the SARS-CoV-2 main protease.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Drug Repositioning/methods , Pneumonia, Viral/drug therapy , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Betacoronavirus/chemistry , Betacoronavirus/enzymology , COVID-19 , Coronavirus 3C Proteases , Coronavirus Infections/virology , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/metabolism , Drug Repositioning/economics , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Oligopeptides/chemistry , Oligopeptides/pharmacology , Pandemics , Pneumonia, Viral/virology , Protease Inhibitors/chemistry , SARS-CoV-2 , Tetracyclines/chemistry , Tetracyclines/pharmacology , Thermodynamics , Time Factors , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism
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