SARS-CoV-2 spike protein S1 receptor-binding domain (S1 RBD)

The SARS-CoV-2 spike protein S1 receptor-binding domain (S1 RBD) is a critical region within the spike glycoprotein of SARS-CoV-2, comprising the main interface for binding the virus to the angiotensin-converting enzyme 2 (ACE2) receptor on host cells, initiating viral entry. The spike protein consists of two subunits, S1 (responsible for receptor binding) and S2 (responsible for membrane fusion); the S1 subunit includes the N-terminal domain (NTD) and the receptor-binding domain (RBD), with the RBD located at the C-terminal portion of S1[1][3][5][6]. The S1 RBD binds directly to ACE2, and this interaction is essential for viral infectivity[1][2][4][6]. The region is the principal target for neutralizing antibodies, making it central to vaccine design, therapeutic monoclonal antibody development, and diagnostics. However, the RBD is also highly mutable, with mutations contributing to increased infectivity, immune escape, and the emergence of new viral variants (Alpha, Beta, Gamma, Delta, Omicron, etc.)[4][6]. Drugs or antibodies targeting the S1 RBD seek to prevent the virus from binding to ACE2, thus blocking infection. The RBD’s antigenicity and sequence conservation are key considerations in the effectiveness and durability of immunity and therapeutic interventions[1][3][6].

Other names

Spike protein S1 RBDSpike glycoprotein S1 receptor-binding domainS1-RBDReceptor-binding domain of spike proteinSARS-2 spike RBD

Inhibits virus-receptor interaction (ACE2 binding blockade); Neutralizing by antibody binding to RBD; Prevents viral entry into host cell