Spike glycoprotein of SARS-CoV-2 (SARS-CoV-2 S protein)

The Spike glycoprotein of SARS-CoV-2 is a large, trimeric class I fusion protein (~180–200 kDa) located on the surface of the virus and responsible for binding to the angiotensin-converting enzyme 2 (ACE2) receptor on host cells, facilitating viral entry and membrane fusion. It is composed of two subunits: S1 (for receptor binding) and S2 (for membrane fusion). The spike protein is the principal antigen recognized by the host immune system, and most COVID-19 vaccines and antibody therapies directly target its receptor-binding domain (RBD) to prevent infection. Its frequent structural variation and glycosylation patterns contribute to immune escape and evolving resistance, especially in emerging variants. Other SARS-CoV-2 proteins (nucleocapsid, membrane, envelope, accessory proteins) may also act as antigens but are less relevant for drug and vaccine targeting.

Other names

Spike proteinS proteinSARS-CoV-2 spikeS glycoproteinE2 glycoprotein (historical)Coronavirus spike protein

Blockade of receptor binding (preventing interaction with ACE2) - Inhibition of membrane fusion (preventing viral entry) - Induction of an immune response, leading to neutralization and clearance