CoV-S [819-919]

General information on CoV-S [819-919]

The new coronavirus strain, SARS-CoV-2, interacts with the human cellular receptor ACE2 through a series of complex mechanisms involving binding, proteolytic cleavage, membrane fusion. This process is mediated by the spike glycoprotein or protein S, which hides in its complex structure multiple short peptide domains that are crucial at different points of the interaction process.
The 101 amino acid long domain comprised between residues 819 and 919 is located at the head region of the S2 subunit of the spike glycoprotein of SARS-CoV-2. After proteolytic cleavage of the spike glycoprotein at the S1/S2 boundary (furin cleavage site), this short domain becomes exposed. This small region could potentially contain the fusion peptide (S812 to F855), an unmasked S2 region responsible for mediating the fusion between the cellular and viral membranes.
The fusion peptide also referred to as FP, is a conserved region of the viral family consisting mostly of hydrophobic residues (like glycine or alanine). These residues, extremely sensitive to point points, trigger the fusion event between the two membranes. Studies with cryo-EM show that the fusion peptide is partially exposed on the surface of SARS-CoV and MERS-CoV, suggesting that this exposure on the prefusion state may be an important feature of coronaviruses.
Due to the high similarity of this region to its homologs in SARS-CoV and MERS-CoV, antibodies targeting this domain could potentially confer broad-spectrum protection against pandemic strains of coronavirus. For this reason, this domain is an attractive alternative to therapies and vaccines targeting the receptor-binding domain (RBD), which at the moment is the preferred target for the development of solutions to mitigate the COVID-19 pandemic.