SARS-CoV-2 spike glycoprotein N-terminal domain and non-RBD epitopes (SARS-CoV-2 S-non-RBD)

The non-RBD (receptor-binding domain) epitopes of the SARS-CoV-2 spike glycoprotein, primarily comprising the N-terminal domain (NTD) and the S2 subunit, are essential components for viral attachment and host cell entry. The NTD contains a well-characterized supersite of vulnerability that is a major target for neutralizing antibodies, although it frequently undergoes mutations and deletions in variants of concern to facilitate immune escape (McCallum et al., 2021, Science). The S2 subunit is highly conserved and contains the machinery required for membrane fusion, including the fusion peptide and heptad repeats, making it an attractive target for broadly neutralizing antibodies (Pinto et al., 2021, Science). Antibodies targeting these regions, such as 4A8 or S2P6, neutralize the virus by interfering with auxiliary receptor binding or blocking the structural rearrangements necessary for fusion (Chi et al., 2020, Science). These epitopes are critical for the development of next-generation vaccines and therapeutics aimed at providing broad protection against diverse SARS-CoV-2 variants and other sarbecoviruses (Harvey et al., 2021, Nature Reviews Microbiology). Furthermore, targeting non-RBD regions can synergize with RBD-directed therapies to reduce the risk of treatment-resistant viral mutants (Cerutti et al., 2021, Cell Host & Microbe). The structural complexity of these regions, particularly the glycan shielding of the NTD, presents unique challenges for drug design but also offers opportunities for high-specificity binding (Soh et al., 2020, Nature).

Other names

NTDN-terminal domainNTD supersiteS1-NTDS2 subunitFusion peptideStem helixHeptad repeat 1Heptad repeat 2Non-RBD epitopes

Inhibition of viral entry through blockade of auxiliary receptor binding, prevention of spike protein conformational transitions, or direct interference with membrane fusion.