Spike glycoprotein of SARS-CoV-2 Omicron variant (Spike (S) protein)

The **spike glycoprotein of SARS-CoV-2 Omicron variant** is a trimeric, class I viral fusion protein that decorates the surface of the SARS-CoV-2 virion and mediates attachment to host cells and subsequent fusion of viral and cellular membranes[4][1][2]. The spike protein is composed of two subunits: S1, which contains the receptor-binding domain (RBD) that engages the host cell receptor angiotensin-converting enzyme 2 (ACE2), and S2, which facilitates membrane fusion[4][7]. The Omicron variant includes sublineages like BA.1, BA.2, and KP.2, and is notable for bearing an unusually high number of mutations in the spike protein, especially in the RBD and N-terminal domain (NTD), which lead to increased transmissibility, altered cell entry preference, and significant evasion of neutralizing antibodies from prior infection or vaccination[1][2][3][5]. These extensive mutations not only remodel spike’s antigenic surfaces but also impact its fusogenic capacity and pathway preference (favoring endosomal entry over direct plasma membrane fusion)[2]. Due to these properties, the Omicron spike is a major determinant of infectivity, immune evasion, and therapeutic antibody efficacy in SARS-CoV-2 infection.

Other names

S proteinsurface glycoproteinspike proteinSARS-CoV-2 SpikeS glycoprotein

Inhibition of spike-ACE2 binding; Neutralization of spike RBD; Prevention of membrane fusion