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Viruses ; 13(10)2021 09 25.
Article in English | MEDLINE | ID: covidwho-1438747


Recently, two cases of complete remission of classical Hodgkin lymphoma (cHL) and follicular lymphoma (FL) after SARS-CoV-2 infection were reported. However, the precise molecular mechanism of this rare event is yet to be understood. Here, we hypothesize a potential anti-tumor immune response of SARS-CoV-2 and based on a computational approach show that: (i) SARS-CoV-2 Spike-RBD may bind to the extracellular domains of CD15, CD27, CD45, and CD152 receptors of cHL or FL and may directly inhibit cell proliferation. (ii) Alternately, upon internalization after binding to these CD molecules, the SARS-CoV-2 membrane (M) protein and ORF3a may bind to gamma-tubulin complex component 3 (GCP3) at its tubulin gamma-1 chain (TUBG1) binding site. (iii) The M protein may also interact with TUBG1, blocking its binding to GCP3. (iv) Both the M and ORF3a proteins may render the GCP2-GCP3 lateral binding where the M protein possibly interacts with GCP2 at its GCP3 binding site and the ORF3a protein to GCP3 at its GCP2 interacting residues. (v) Interactions of the M and ORF3a proteins with these gamma-tubulin ring complex components potentially block the initial process of microtubule nucleation, leading to cell-cycle arrest and apoptosis. (vi) The Spike-RBD may also interact with and block PD-1 signaling similar to pembrolizumab and nivolumab- like monoclonal antibodies and may induce B-cell apoptosis and remission. (vii) Finally, the TRADD interacting "PVQLSY" motif of Epstein-Barr virus LMP-1, that is responsible for NF-kB mediated oncogenesis, potentially interacts with SARS-CoV-2 Mpro, NSP7, NSP10, and spike (S) proteins, and may inhibit the LMP-1 mediated cell proliferation. Taken together, our results suggest a possible therapeutic potential of SARS-CoV-2 in lymphoproliferative disorders.

COVID-19/metabolism , Lymphoma/immunology , SARS-CoV-2/immunology , Antibodies, Monoclonal/immunology , Antineoplastic Agents/pharmacology , Binding Sites , COVID-19/complications , Glycoproteins/metabolism , Glycoproteins/ultrastructure , Humans , Immunity/immunology , Lymphoma/therapy , Lymphoma/virology , Models, Theoretical , Molecular Docking Simulation , Protein Binding , Protein Domains , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/ultrastructure , Viroporin Proteins/metabolism , Viroporin Proteins/ultrastructure
Nat Commun ; 11(1): 3070, 2020 06 17.
Article in English | MEDLINE | ID: covidwho-606969


Porcine coronavirus SADS-CoV has been identified from suckling piglets with severe diarrhea in southern China in 2017. The SADS-CoV genome shares ~95% identity to that of bat α-coronavirus HKU2, suggesting that SADS-CoV may have emerged from a natural reservoir in bats. Here we report the cryo-EM structures of HKU2 and SADS-CoV spike (S) glycoprotein trimers at 2.38 Å and 2.83 Å resolution, respectively. We systematically compare the domains of HKU2 spike with those of α-, ß-, γ-, and δ-coronavirus spikes, showing that the S1 subunit N- and C-terminal domains of HKU2/SADS-CoV are ancestral domains in the evolution of coronavirus spike proteins. The connecting region after the fusion peptide in the S2 subunit of HKU2/SADS-CoV adopts a unique conformation. These results structurally demonstrate a close evolutionary relationship between HKU2/SADS-CoV and ß-coronavirus spikes and provide insights into the evolution and cross-species transmission of coronaviruses.

Alphacoronavirus/chemistry , Spike Glycoprotein, Coronavirus/ultrastructure , Animals , Cell Line , Chiroptera , Coronavirus Infections , Cryoelectron Microscopy , Evolution, Molecular , Glycoproteins/ultrastructure , Humans , Models, Molecular , Protein Domains , Swine
Nat Commun ; 11(1): 2688, 2020 05 27.
Article in English | MEDLINE | ID: covidwho-432476


Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses (CoVs) are zoonotic pathogens with high fatality rates and pandemic potential. Vaccine development focuses on the principal target of the neutralizing humoral immune response, the spike (S) glycoprotein. Coronavirus S proteins are extensively glycosylated, encoding around 66-87 N-linked glycosylation sites per trimeric spike. Here, we reveal a specific area of high glycan density on MERS S that results in the formation of oligomannose-type glycan clusters, which were absent on SARS and HKU1 CoVs. We provide a comparison of the global glycan density of coronavirus spikes with other viral proteins including HIV-1 envelope, Lassa virus glycoprotein complex, and influenza hemagglutinin, where glycosylation plays a known role in shielding immunogenic epitopes. Overall, our data reveal how organisation of glycosylation across class I viral fusion proteins influence not only individual glycan compositions but also the immunological pressure across the protein surface.

Glycoproteins/immunology , Middle East Respiratory Syndrome Coronavirus , Polysaccharides , Spike Glycoprotein, Coronavirus/immunology , Viral Fusion Proteins/immunology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Cryoelectron Microscopy , Epitopes/chemistry , Epitopes/immunology , Epitopes/metabolism , Glycoproteins/chemistry , Glycoproteins/ultrastructure , Glycosylation , HEK293 Cells , HIV-1/immunology , HIV-1/metabolism , Humans , Immune Evasion/physiology , Lassa virus/immunology , Lassa virus/metabolism , Middle East Respiratory Syndrome Coronavirus/immunology , Middle East Respiratory Syndrome Coronavirus/metabolism , Orthomyxoviridae/immunology , Orthomyxoviridae/metabolism , Polysaccharides/chemistry , Polysaccharides/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/ultrastructure , Viral Fusion Proteins/chemistry , Viral Fusion Proteins/ultrastructure , Viral Proteins/chemistry , Viral Proteins/immunology , Viral Proteins/ultrastructure