SARS-CoV-2 spike glycoprotein S1 subunit (S1) (S1)

The SARS-CoV-2 spike glycoprotein S1 subunit is a critical viral surface protein that mediates the initial attachment of the virus to host cells. It contains the receptor-binding domain (RBD), which specifically recognizes and binds to the human angiotensin-converting enzyme 2 (ACE2) receptor [1, 2]. This interaction is the primary determinant of viral host range and tissue tropism, making the S1 subunit the most significant target for neutralizing antibodies and vaccine development [4, 5]. Upon binding to ACE2, the S1 subunit undergoes conformational changes that facilitate the subsequent membrane fusion process mediated by the S2 subunit [3, 9]. Most therapeutic monoclonal antibodies, such as bamlanivimab and sotrovimab, function by binding to the S1 RBD and sterically hindering its interaction with ACE2 [1, 10]. However, the S1 subunit is highly prone to mutations, particularly in the RBD and N-terminal domain (NTD), which can lead to the emergence of variants that escape existing immunity [8, 10]. Consequently, monitoring mutations in this domain is vital for assessing the efficacy of current vaccines and therapeutics [2, 7]. The S1 subunit also serves as a key biomarker for diagnosing past or present infections through the detection of S1-specific antibodies or antigens [5, 11].

Other names

Spike protein S1 subunitSARS-CoV-2 S1S1 domainSurface glycoprotein S1 subunit

Neutralization of viral entry by blocking the interaction between the S1 receptor-binding domain (RBD) and the host angiotensin-converting enzyme 2 (ACE2) receptor [1, 2, 10].