Spike glycoprotein S1 N-terminal domain (S1-NTD)

The Spike glycoprotein S1 N-terminal domain (S1-NTD) is a distinct region within the S1 subunit of the coronavirus spike (S) protein, located at the N-terminus, and structurally characterized by a galectin-like fold[1][3][8]. In SARS-CoV-2 and related coronaviruses, the spike protein mediates viral entry into host cells, with S1 responsible for receptor interactions and S2 for membrane fusion[1][2][6][8]. The S1-NTD plays a critical role in viral attachment to the host by binding sugars (such as sialic acid) or, in some coronaviruses, protein receptors[3][5][8]. It is a major target for host neutralizing antibodies and contributes to immune evasion, but it is less conserved than other spike regions, allowing antigenic variation and escape from immunity[3][5]. While most therapeutic development for SARS-CoV-2 has focused on the receptor-binding domain (RBD) of S1, several monoclonal antibodies target the NTD, some of which are studied for treatment or prevention of COVID-19, though viral mutations can compromise efficacy[5]. The S1-NTD is thus a bona fide therapeutic target and a key antigenic determinant in the SARS-CoV-2 infection process[1][3][5].

Other names

N-terminal domain of SARS-CoV-2 S1 subunitS1-NTDNTD of spike protein

Neutralizing antibodies block virus attachment or induce conformational changes preventing entry; Potential small molecules or mimetics blocking glycan/sugar binding (experimental)