Fine structure of influenza a virus observed by electron cryomicroscopy

Cryo-electron microscopy of viruses. Morphogenesis of influenza A virus in Ehrlich ascites tumor cells as revealed by thin-sectioning and freeze-etching. J Virol. Phosphorus assay in column chromatography. J Biol Chem. A rapid method of total lipid extraction and purification.

Can J Biochem Physiol. Electron microscopy of influenza virus. A comparison of negatively stained and ice-embedded particles. J Mol Biol. Crystalline antigen from the influenza virus envelope. Nat New Biol. Incorporation of influenza virus M-protein into liposomes.

Structure of the catalytic and antigenic sites in influenza virus neuraminidase. Influenza virus proteins. Analysis of polypeptides of the virion and identification of spike glycoproteins. Quantification of Coomassie Blue stained proteins in polyacrylamide gels based on analyses of eluted dye.

Anal Biochem. Expression of wild-type and mutant forms of influenza hemagglutinin: the role of folding in intracellular transport.

Interaction of influenza M protein with viral lipid and phosphatidylcholine vesicles. Replication of influenza A and B viruses in human diploid cells. J Gen Virol. The detection and classification of membrane-spanning proteins. Biochim Biophys Acta. Activation of influenza A viruses by trypsin treatment. A simple method for displaying the hydropathic character of a protein. Cleavage of structural proteins during the assembly of the head of bacteriophage T4.

The gene structure and replication of influenza virus. Annu Rev Biochem. Structure of oriented lipid bilayers. Protein measurement with the Folin phenol reagent. Activation of influenza virus by acidic media causes hemolysis and fusion of erythrocytes.

FEBS Lett. B The molecular docking of synthesized compound EMT and hemagglutinin in host cell reveals the binding affinity receptor and seeding region of the possible interaction between the inhibitor EMT and sialic acid. Our findings here indicate novel and active water soluble compounds EMT and EMT against IAV infection without detectable toxic effect on cell viability and cell proliferation.

These identified compounds have the ability to disturb virus entry via binding with sialic acid in cell receptors and decrease the connection chance of viral hemagglutinin and host cell surface. Recently, solubility of chemical compounds in aqueous buffer has become a critical issue in drug discovery to prevent several barriers in biological challenge assays. For instance, Dimethyl sulfoxide DMSO is an organic compound with a median lethal dose higher than ethanol usually used at concentration of 30 mM to dissolve hydrophobic compounds Papaneophytou et al.

Noteworthy, when absorbed through skin, DMSO causes contamination and unexpected harmful cytotoxic effects in cellular function resulted in suppression of cell proliferation Oz et al. Thus, the current data provide novel and active candidates that can inhibit IAV entry to host cells with high solubility in aqueous buffer. Accordingly, virus particles in the rest of infectious media was quantified upon the primary infection to investigate the possible interruption of virus entry to treated cells.

Interestingly, both luciferase assay and plaque assay showed high concentration of virus particles remained in infectious media used to infect A cells that treated with both EMT and EMT compared to control treated cells.

Several studies demonstrate that IAV enters the host through the binding between viral HA and sialic acid as an initial receptor Wagner et al. Subsequently, the viral nucleocapsids transfer to the host nucleus for the primary transcription to produce necessary proteins for replication such as PB1 protein.

Once the initial proteins are made, eight positive sense cRNA strands are transcribed from the eight negative sense RNA segments which produce again a negative sense RNA and translated to major virus proteins Nayak et al.

Then the proteins assemble with the other matrix protein M1 , and begin the budding process Pinto and Lamb, a , b ; Bouvier and Palese, Finally, viral neuraminidase cleaves the binding site between hemagglutinin and cell receptors to facilitate the virus release Schmitt and Lamb, ; Sidorenko and Reichl, Notably, viral NP protein is a major component of ribonucleoprotein complex which plays the critical role in RNA transcription and viral replication.

Excluding the possibility of viral escape mutation, targeting of NP protein disturbs transcription, replication and intracellular trafficking of the virus genome Portela and Digard, ; Turrell et al. Other studies have been shown that viral NS1 protein inhibits the innate and adaptive immune response by multiple mechanisms.

These findings further confirm that the selected chemical compounds have the ability to disturb IAV entry to the host. One explanation of this disturbing of virus entry in treated cells is the interaction between indicated compounds and cellular hemagglutinin receptors through binding with sialic acid.

The synthesized compounds EMT and EMT were investigated for the binding affinity of sialic acid receptor for the purpose of lead optimization and to find out the interaction between the indicated compounds and the sialic acid receptor. Sialic acids Sias are a family of nine carbon monosaccharides that are usually found on the outermost capping positions of glycans that are linked to cell-surface glycoproteins and glycolipids Schauer, Interestingly, our docking analysis that investigate the possible interaction between the chemical inhibitors and hemagglutinin in cell receptors reveals high priority of the binding between these compounds and sialic acid in host cells.

Together, these findings reveal that the active selected compounds inhibit IAV infection in treated cells and reduced viral replication via disturbing of virus entry. Further, these active compounds need to be investigated in vivo by intratracheal delivering of selected inhibitors into the mice model following by virus inoculations and monitoring the lung virus loads. HK planned and designed the study. TE prepared the chemical inhibitors. HK wrote the manuscript. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The authors thank Prof. Khalil laboratory through project ID: Bouvier, N. The biology of influenza viruses. Vaccine 26, D49—D Cai, J. Inhibition of influenza infection by glutathione. Free Radic. Claas, E. Human influenza A H5N1 virus related to a highly pathogenic avian influenza virus.

Lancet , — Cyranoski, D. Threat of pandemic brings flu drug back to life. Dyer, B. A noncommercial dual luciferase enzyme assay system for reporter gene analysis. Fillon, H. New chemical synthesis of functionalized arylzinc compounds from aromatic or thienyl bromides under mild conditions using a simple cobalt catalyst and zinc dust. Fraser, C. Pandemic potential of a strain of influenza A H1N1 : early findings.

Science , — Fujiyoshi, Y. Fine-structure of influenza-A virus observed by electron cryomicroscopy. Embo J. Google Scholar.

Hao, L. Drosophila RNAi screen identifies host genes important for influenza virus replication. Nature , U—U Hatada, E. Mutant influenza viruses with a defective NS1 protein cannot block the activation of PKR in infected cells. PubMed Abstract Google Scholar. Holmes, E. Whole-genome analysis of human influenza A virus reveals multiple persistent lineages and reassortment among recent H3N2 viruses. PLoS Biol. Karlas, A. Brian D. Joel D. Ronald A. Michael J. Author information Article notes Copyright and License information Disclaimer.

This article is made available via the PMC Open Access Subset for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. This article has been cited by other articles in PMC.

Go to:. The transmissible gastroenteritis coronavirus contains a spherical core shell consisting of M and N proteins. Electron microscopy of influenza virus. A comparison of negatively stained and ice-embedded particles, J. Fine structure of influenza A virus observed by electron cryo-microscopy. EMBO J. Morphological changes and fusogenic activity of influenza virus hemagglutinin.

Specific interaction of a novel foamy virus Env leader protein with the N-terminal Gag domain. Structural organization of authentic, mature HIV-1 virions and cores. Cryo-electron microscopy reveals ordered domains in the immature HIV-1 particle. Projection structures of human immunodeficiency virus type1 HIV-1 observed with high resolution electron cryo-microscopy.

Electron Microsc. Tokyo ; 43 — Organization of immature human immunodeficiency virus type 1. Supramolecular organization of immature and mature murine leukemia virus revealed by electron cryo-microscopy: implications for retroviral assembly mechanisms. The organization of mature Rous sarcoma virus as studied by cryoelectron microscopy. Characterization of Rous sarcoma virus Gag particles assembled in vitro.

Electron microscopy of vitrified-hydrated La Crosse virus. Structural variation of La Crosse virions under different chemical and physical conditions.

Hosaka Y, Watabe T. Cryoelectron microscopy of vitrified Sendai virions. Complementarity in the supramolecular design of arenaviruses and retroviruses revealed by electron cryomicroscopy and image analysis. Ribonucleoprotein-like structures from coronavirus particles.

Geography of a virus: Using a technique called single-particle electron cryomicroscopy, the protein shell—called a capsid—of the epsilon 15 virus was imaged in unprecedented detail. Multimedia See other pictures of the virus. Watch a movie of the virus model. Keep Reading. Most Popular. Deepfake researchers have long feared the day this would arrive. By Karen Hao archive page. By Charlotte Jee archive page. By Lucas Laursen archive page. By Tanya Basu archive page. Stay connected Illustration by Rose Wong.