Synthetic Neutralizing Peptides Inhibit the Host Cell Binding of Spike Protein and Block Infection of SARS-CoV-2.

Antiviral treatments of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been extensively pursued to conquer the pandemic. To inhibit the viral entry to the host cell, we designed and obtained three peptide sequences via quartz crystal microbalance measurement screening, which showed high affinity at nanomole to the S1 subunit of the spike protein and wild-type SARS-CoV-2 pseudovirus. Circular dichroism spectroscopy measurements revealed significant conformation changes of the S1 protein upon encounter with the three peptides. The peptides were able to effectively block the infection of a pseudovirus to 50% by inhibiting the host cell lines binding with the S1 protein, evidenced by the results from Western blotting and pseudovirus luciferase assay. Moreover, the combination of the three peptides could increase the inhibitory rate to 75%. In conclusion, the three chemically synthetic neutralizing peptides and their combinations hold promising potential as effective therapeutics in the prevention and treatment of COVID-19.