The SARS-CoV-2 spike protein (S-protein) is a structural, transmembrane protein that is displayed on the surface of the viral particle. Also referred to as the "glycoprotein," the S-protein performs two primary tasks that aid in host infection: 1) mediates the attachment between the virus and host cell surface receptors, and 2) facilitates viral entry into the host cell by assisting in the fusion of the viral and host cell membranes. Of particular importance is the receptor binding domain (RBD) on subunit 1 (Figure 1), which must bind the host's ACE2 receptor for the virus to enter the cell.

Due to its pivotal role in SARS-CoV-2 infection, the S-protein is the primary target for vaccine and drug developers. However, the emergence of spike variants has caused widespread concern since they could perpetuate the spread of COVID-19. Spike mutations may, for example, impact the efficacy of COVID-19 vaccines and therapeutic drugs, the accuracy of diagnostic assays. increase the viral transmission rate, or cause more severe disease symptoms. SARS-CoV-2 variants have thus been classified as variants of interest, concern, or high consequence based on their prevalence and their predicted or known impact on SARS-CoV-2 countermeasures.

RayBiotech also offers recombinant Spike protein variants. Learn more about 3 crucial Spike protein variants of concern [B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma)] in our blog, SARS-CoV-2 Variants: An Emerging Landscape of Therapeutic Targets.

SARS-CoV-2 Spike (S) protein domains

Viral entry the interaction between the Spike protein's receptor binding domain (RBD) and the host's ACE2 receptor. Other host receptors (NRP1, AXL, Basigin, GRP-78) assist in viral entry. The numbers below the domains show the amino acid position.