Receptor-binding domain of the SARS-CoV-2 spike protein (RBD (of SARS-CoV-2 spike protein))

The receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) protein is a critical region within the S1 subunit (amino acids approximately 319–541) that directly binds to the human ACE2 receptor to initiate viral entry into host cells. The spike protein is a trimeric, heavily glycosylated viral surface glycoprotein essential for virus attachment, fusion, and entry, with the RBD mediating the first step—recognition and attachment to host cells. The RBD is the principal target for neutralizing antibodies in natural infection and vaccination, and is a primary determinant of viral infectivity and immune escape. Therapeutic monoclonal antibodies and vaccine-induced antibodies act mainly by blocking the interaction between the RBD and ACE2, thereby preventing infection. Mutations within the RBD are a major source of viral variants of concern, influencing transmissibility, immune evasion, and therapeutic resistance, making the RBD one of the most intensively studied therapeutic and diagnostic targets in COVID-19 research and intervention.

Other names

Spike RBDSARS-CoV-2 S RBDS1 receptor-binding domainSARS-CoV-2 spike receptor-binding domain

Neutralization (antibodies block RBD-ACE2 interaction); Inhibition of viral attachment/entry; Prevention of conformational changes needed for membrane fusion