Spike glycoprotein (coronavirus) (S protein)

The **spike glycoprotein** of coronaviruses is a large, trimeric, transmembrane protein forming prominent projections (“spikes”) on the viral envelope, giving the virus its characteristic appearance[1][6]. It mediates viral entry by first binding to host cell surface receptors such as angiotensin-converting enzyme 2 (ACE2), then enabling membrane fusion via its class I fusion protein machinery[1][2][6]. The protein is divided into S1 (receptor binding) and S2 (fusion) subunits, with activation by host proteases (notably furin and TMPRSS2) being essential for viral infectivity[2][4][6]. The spike glycoprotein is highly immunogenic and central to generating neutralizing antibodies; it is thus the main antigenic component of all major COVID-19 vaccines and the principal target of therapeutic antibodies[1][3][4][7]. Mutation in spike (e.g., D614G) can affect infectivity, immune escape, and vaccine efficacy[5]. Spike glycoprotein is the primary focus for diagnostics, therapeutic targeting, and immunological monitoring in COVID-19 and related coronavirus infections[3][5][6].

Other names

Spike proteinS glycoproteinS proteinE2 protein (historical)SARS-CoV-2 S proteinSARS spike glycoprotein

Blockade of receptor binding domain (prevents attachment to ACE2 and other host receptors) - Inhibition of membrane fusion (prevents viral and host membrane fusion events) - Cleavage inhibition (prevents activation of the fusion peptide by host proteases) - Antibody-dependent neutralization (prevents viral entry by neutralizing virus particles)