Betacoronavirus spike protein (S protein)

The Betacoronavirus spike protein is a large, trimeric type I transmembrane glycoprotein that forms the characteristic crown-like appearance on the surface of coronaviruses, such as SARS-CoV-2, SARS-CoV, and MERS-CoV (UniProt P0DTC2). It is the primary protein responsible for viral entry into host cells, consisting of two functional subunits: S1, which contains the receptor-binding domain (RBD) for attachment to host receptors like ACE2 or DPP4, and S2, which mediates the fusion of the viral and host cell membranes (V'kovski et al., 2021). Due to its essential role in the viral life cycle and its exposure on the viral envelope, the spike protein is the principal target for neutralizing antibodies and the primary focus of vaccine development (Huang et al., 2020). Multi-epitope antigens are engineered vaccine constructs that combine multiple immunogenic segments of the spike protein to elicit a broad and robust immune response, aiming to provide protection against diverse viral variants (Li, 2016). Therapeutic strategies targeting the spike protein include monoclonal antibodies that sterically hinder receptor binding and various vaccine platforms that prime the immune system to recognize the protein (NIH, 2023). The protein's high rate of mutation, particularly in the RBD, presents a significant challenge for long-term therapeutic efficacy and vaccine durability.

Other names

S proteinSpike glycoproteinSurface glycoproteinBetacoronavirus S proteinMulti-epitope spike antigen

Monoclonal antibodies bind to the receptor-binding domain (RBD) of the spike protein to block its interaction with host cell receptors (e.g., ACE2), preventing viral entry. Vaccines utilize the spike protein or its genetic sequence to induce neutralizing antibodies and cellular immunity that recognize and neutralize the virus upon exposure (NIH, 2023; Huang et al., 2020).