Spike glycoprotein S (S protein)

The **Spike glycoprotein S** is a large viral surface protein found in coronaviruses, including SARS-CoV-2, SARS-CoV, and MERS-CoV[1][3][5]. It assembles as a trimer that decorates the viral surface and is essential for mediating viral entry into host cells by binding host receptors (such as ACE2 for SARS-CoV-2)[1][3][6]. The spike protein consists of two main subunits: S1 contains the receptor-binding domain (RBD), responsible for host cell recognition, while S2 oversees fusion of the viral and cellular membranes, enabling the virus to infect its target[1][2][3][4][5]. Heavily glycosylated and highly immunogenic, the spike protein is the principal target of neutralizing antibodies and serves as the antigen in all current COVID-19 vaccines[1][5][6]. It undergoes significant conformational changes for function and is subject to mutations that can impact infectivity and vaccine efficacy[3][4][8]. Thus, it is a critical **therapeutic target** for antiviral drugs, monoclonal antibodies, and vaccine development and is central to biomarker assays for COVID-19 diagnosis and immune status monitoring[1][3][5].

Other names

Spike proteinS glycoproteinS proteinS (E2, in older nomenclature)SARS-CoV-2 spike proteincoronavirus spike protein

Inhibition of receptor binding, Neutralization of viral entry, Antibody-dependent cellular cytotoxicity, Inhibition of conformational changes required for membrane fusion