SARS-CoV-2 spike protein N-terminal domain (NTD)

The SARS-CoV-2 spike protein N-terminal domain (NTD) is a critical structural component of the S1 subunit of the viral spike glycoprotein. It possesses a galectin-like fold and is primarily involved in the initial attachment of the virus to host cells, potentially through interactions with sialic acids, glycans, or proteinaceous co-receptors like AXL and various lectins [11, 14]. While the receptor-binding domain (RBD) is the primary site for ACE2 interaction, the NTD contains an 'antigenic supersite' that is a major target for potent neutralizing antibodies found in convalescent patients [10, 12]. Mutations within the NTD, particularly in its five flexible loops (N1-N5), are frequently observed in variants of concern and contribute significantly to immune evasion and altered viral tropism [9, 12]. Therapeutic strategies targeting the NTD, such as monoclonal antibodies like 4A8, aim to neutralize the virus by blocking attachment or stabilizing the spike in a non-functional prefusion state [1, 6]. Although often considered secondary to the RBD, the NTD is an essential target for developing cocktail therapies and next-generation vaccines to provide broader protection against evolving SARS-CoV-2 strains [15, 23].

Other names

Spike NTDS1-NTDN-terminal domain of the spike proteinSARS-CoV-2 S1 subunit N-terminal domain

Neutralization of viral entry by inhibiting host cell attachment, blocking interactions with co-receptors such as AXL or lectins, and preventing the prefusion-to-postfusion conformational change of the spike protein.