SpikeProtein
Spike protein, or S protein, is a transmembrane glycoprotein on the surface of coronaviruses. It is a trimeric class I fusion protein responsible for attachment to host cells and fusion of viral and cellular membranes. The spike gene S encodes a precursor that is cleaved into two subunits, S1 and S2. S1 contains the receptor-binding domain, which recognizes the host cell receptor, and an N-terminal domain that contributes to receptor engagement and antigenicity. S2 houses the fusion machinery, including the fusion peptide, heptad repeats HR1 and HR2, the transmembrane domain, and the cytoplasmic tail. The protein is heavily glycosylated, contributing to the glycan shield that can modulate immune recognition.
During entry, the spike protein binds its receptor (for SARS-CoV-2, ACE2), and host proteases cleave at the
Spike proteins are central to vaccines and antibody responses, being the main target of neutralizing antibodies.