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Principal Investigator: Susan Daniel
Organization: CORNELL UNIVERSITY
Fiscal Year: 2021
Award: $174,298
Funding agency: National Institute of Allergy and Infectious Diseases
Project Summary / Abstract
Enveloped viruses access their host cells by binding to receptors on the plasma membrane and then undergoing
fusion with the host membrane. Both binding and fusion are mediated by a specific viral “spike” protein that is
typically primed for fusion activation by proteolytic cleavage to expose the fusion peptide. Coronavirus fusion
spike protein (CoV S) is a complex biomolecular machine that has a novel fusion peptide with has a great deal
of inherent flexibility in its fusion reaction. This is exploited by these viruses in their diverse entry pathways and
is a primary determinant of viral tropism. We have pioneered the concept that that the proteolytic cleavage events
in S that lead to membrane fusion occur both at the interface of the receptor binding (S1) and fusion (S2) domains
(called S1/S2), as well as adjacent to a structurally and functionally novel fusion peptide within S2 (called S2’).
Thus, there are notable differences between CoV S and most other class I fusion proteins including: 1) that the
proteolytic events liberating the fusion peptide are diverse, and 2) that the fusion peptide itself is atypical in
sequence compared to other fusion peptides, containing a mixture of important hydrophobic and negatively-
charged residues, and may represent a larger than normal fusion “platform” instead of a defined “peptide”. Thus
fusion peptide activity is likely controlled by reorganization of the fusion platform, based on both hydrophobic
(i.e. lipid-binding) and ionic (i.e. Ca2+) interactions. Despite the recent availability of S structures in their pre-
fusion state, there remains a very limited mechanistic understanding of membrane fusion for the CoV family, or
any structural information to correlate structural biology aspects of S to its function in membrane fusion. This
information is critical to understanding viral pathogenesis and CoV emergence into the human population. We
propose an integrated biophysical, biochemical, and in vivo approach to study the unique cleavage-activated
regulation of CoV S protein, using Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute
respiratory syndrome coronavirus (SARS-CoV) as primary models. We will use state-of-the-art spectroscopy
and an innovative single particle tracking technique to study S protein fusion peptide function, and combine these
with in vivo infectivity studies, including at BSL3, will allow a complete picture of CoV fusion activation. These
approaches will reveal how structure and function vary depending on the key activators of S; i.e. receptor binding,
protease availability and the local ionic environment. These studies will allow us to determine common principals
that can be applied to all CoVs, moving the field forward with these innovative studies will provide critical
knowledge about CoV entry and tropism needed to safeguard human health from an emerging pathogen likely
to cause severe outbreaks, and for which few or no medical countermeasures exist.
Terms: <AIDS Virus><Acquired Immune Deficiency Syndrome Virus><Acquired Immunodeficiency Syndrome Virus><Animals><Assay><Binding><Bioassay><Biochemical><Biologic Assays><Biologic Models><Biological Assay><Biological Models><Biophysics><Body Tissues><Cell Body><Cell fusion><Cell membrane><Cell surface><Cells><Charge><Chimera Protein><Chimeric Proteins><Cleaved cell><CoV S protein><CoV emergence><CoV glycoprotein S><CoV spike glycoprotein><CoV spike protein><Communicable Diseases><Complex><Coronaviridae><Coronaviridae Infections><Coronavirus><Coronavirus Infections><Coronavirus glycoprotein S><Coronavirus spike protein><Cryo-electron Microscopy><Cryoelectron Microscopy><Cytoplasmic Membrane><Data><Disease Outbreaks><EBOV><EPR spectroscopy><ESR Spectroscopy><Ebola virus><Ebola-like Viruses><Electron Cryomicroscopy><Electron Paramagnetic Resonance><Electron Spin Resonance><Electron Spin Resonance Spectroscopy><Endosomes><Environment><Esteroproteases><Event><Exposure to><Family><Fusion Protein><Genetics-Mutagenesis><Goals><HIV><Health><Human><Human Immunodeficiency Viruses><Hydrophobicity><Infection><Infectious Disease Pathway><Infectious Diseases><Infectious Disorder><Influenza HA><Influenza Hemagglutinin><Investigators><Ions><Knowledge><LAV-HTLV-III><Lead><Lipid Bilayers><Lipid Binding><Lipids><Lymphadenopathy-Associated Virus><MERS><MERS corona virus><MERS coronavirus><MERS coronavirus disease><MERS virus><MERS-CoV><MERS-CoV disease><Mediating><Membrane><Membrane Fusion><Methods><Middle East Respiratory Syndrome><Middle East Respiratory Syndrome CoV disease><Middle East Respiratory Syndrome Corona Virus><Middle East Respiratory Syndrome Coronavirus><Middle East Respiratory Syndrome Virus><Middle East Respiratory Syndrome coronavirus disease><Middle East Respiratory Syndrome-CoV><Middle Eastern Respiratory Syndrome><Middle Eastern Respiratory Syndrome CoV disease><Middle Eastern Respiratory Syndrome Corona virus><Middle Eastern Respiratory Syndrome Coronavirus><Middle Eastern Respiratory Syndrome Virus><Middle Eastern Respiratory Syndrome coronavirus disease><Middle Eastern Respiratory Syndrome-CoV><Model System><Modeling><Modern Man><Molecular Interaction><Monitor><Mutagenesis><Mutagenesis Molecular Biology><NMR Spectrometer><NMR Spectroscopy><Nature><Outbreaks><Paramagnetic Resonance><Pathogenesis><Pathway interactions><Pb element><Peptidases><Peptide Hydrolases><Peptides><Plasma Membrane><Play><Population><Process><Property><Protease Gene><Proteases><Proteinases><Proteins><Proteolytic Enzymes><Reaction><Receptor Protein><Receptosomes><Regulation><Research Personnel><Research Resources><Researchers><Resources><Role><Route><SARS><SARS Virus><SARS corona virus><SARS coronavirus><SARS coronavirus disease><SARS-Associated Coronavirus><SARS-CoV><SARS-CoV disease><SARS-Related Coronavirus><Severe Acute Respiratory Syndrome><Severe Acute Respiratory Syndrome CoV disease><Severe Acute Respiratory Syndrome Virus><Severe Acute Respiratory Syndrome corona virus><Severe Acute Respiratory Syndrome coronavirus><Severe Acute Respiratory Syndrome coronavirus disease><Site><Spectroscopy><Spectrum Analyses><Spectrum Analysis><Structure><Structure-Activity Relationship><Techniques><Testing><Tissues><Transmission><Tropism><UV laboratory microscope><Ultraviolet Microscopes><Viral><Viral Fusion Proteins><Viral Pathogenesis><Viral Receptor><Virus><Virus Receptors><Virus-HIV><Zoonoses><Zoonotic><Zoonotic Infection><base><biophysical approaches><biophysical foundation><biophysical methodology><biophysical methods><biophysical principles><biophysical sciences><biophysical techniques><cell type><chemical structure function><cleaved><corona virus><corona virus emergence><coronavirus S protein><coronavirus emergence><coronavirus spike glycoprotein><cryo-EM><cryoEM><ebolavirus><electron paramagnetic resonance spectroscopy><emergent CoV><emergent corona virus><emergent coronavirus><emerging CoV><emerging corona virus><emerging coronavirus><emerging pathogen><experiment><experimental research><experimental study><flexibility><flexible><flu HA><flu hemagglutinin><fluorescence microscope><fluorescence/UV microscope><fluorescent microscope><heavy metal Pb><heavy metal lead><in vivo><influenza viral HA><influenza viral hemagglutinin><influenza virus HA><influenza virus hemagglutinin><innovate><innovation><innovative><laboratory fluorescence light microscope><lipid bilayer membrane><lipid bound><medical countermeasure><membrane structure><mutant><nCoV><new CoV><new corona virus><new coronavirus><new pathogen><novel><novel CoV><novel corona virus><novel coronavirus><novel pathogen><novel virus><nuclear magnetic resonance spectroscopy><particle><pathway><peptide I><peptide structure><plasmalemma><protein function><receptor><receptor binding><receptor bound><severe acute respiratory syndrome-CoV><social role><structural biology><structure function relationship><transmission process><virus envelope><virus pathogenesis>