Spike glycoprotein of severe acute respiratory syndrome coronavirus (S protein (or S glycoprotein))

The **Spike glycoprotein of severe acute respiratory syndrome coronavirus** (S protein, SARS-CoV spike protein) is a large, trimeric envelope glycoprotein critical for virus infectivity and immune recognition[1][2]. It mediates entry into host cells by binding the host cellular receptor **angiotensin-converting enzyme 2 (ACE2)** through its S1 subunit, and driving viral–host membrane fusion through its S2 subunit[1][2][4]. Spike protein is heavily glycosylated, forms prominent spikes (peplomers) on the virion surface, and is the main target of neutralizing antibodies following infection or vaccination[1][2]. The S protein is proteolytically activated by host proteases (such as TMPRSS2 and Cathepsin B/L), which is a crucial step for viral entry[4]. Because of its essential and exposed role, it is a prime therapeutic target; many experimental antivirals, monoclonal antibodies, and vaccines focus on the spike glycoprotein to prevent or treat SARS infection[2][4]. **Note:** This target is structurally and functionally analogous to the spike glycoprotein of SARS-CoV-2, but it is specific for SARS-CoV-1 (the virus responsible for the 2002–2003 SARS outbreak) and exhibits important sequence differences predominantly in the receptor-binding domain[1].

Other names

Spike proteinS glycoproteinS proteinE2 proteinSARS-CoV spike protein

Inhibition of receptor binding to ACE2 (by neutralizing antibodies or small molecules); Inhibition of S protein priming/cleavage (by protease inhibitors of TMPRSS2/Cathepsin); Inhibition of membrane fusion (by fusion inhibitors targeting S2 domain)