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

The SARS-CoV-2 spike protein receptor-binding domain (RBD) is a critical functional unit within the S1 subunit of the viral spike glycoprotein (UniProt: P0DTC2). Its primary biological role is to facilitate the attachment of the virus to the host cell by binding with high affinity to the Angiotensin-Converting Enzyme 2 (ACE2) receptor (PubMed: 32155444). This binding event is the essential first step for viral entry, triggering conformational changes in the spike protein that lead to membrane fusion and the release of the viral genome into the host cytoplasm (Nature: 583, 2020). Because of its indispensable role in the infection process, the RBD is the primary target for neutralizing antibodies, whether induced by natural infection, vaccination, or administered as therapeutic monoclonal antibodies like Bamlanivimab or Sotrovimab (NIH: COVID-19 Treatment Guidelines). Most clinical interventions for COVID-19 focus on blocking this specific domain to prevent viral attachment and subsequent replication. However, the RBD is also a hotspot for mutations, leading to the emergence of variants of concern that can partially evade existing immune responses and therapeutic treatments (Science: 371, 2021).

Other names

Spike protein RBDS-RBDSARS-CoV-2 S1 subunit RBDReceptor-binding domain of the spike proteinSARS-CoV RBD

Neutralizing antibodies bind to the RBD to sterically hinder its interaction with the host Angiotensin-Converting Enzyme 2 (ACE2) receptor, thereby preventing viral entry into host cells.