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

The SARS-CoV-2 Omicron BA.2 spike protein receptor-binding domain (RBD) is a critical structural component of the viral spike glycoprotein that mediates infection by binding to the human angiotensin-converting enzyme 2 (ACE2) receptor (NIH, 2022). Located within the S1 subunit, the RBD transitions between "up" and "down" conformations to expose its binding interface to host cells (NIH, 2022). The BA.2 subvariant is characterized by a specific set of mutations in the RBD, such as S371F, T376A, D405N, and R408S, which distinguish it from the BA.1 lineage and contribute to its increased transmissibility and significant immune evasion (NIH, 2022; Nature, 2023). This domain serves as the primary target for neutralizing antibodies elicited by vaccines and therapeutic monoclonal antibodies (NIH, 2022). However, the high mutational plasticity of the RBD allows the virus to escape many existing immune responses, necessitating the development of next-generation therapeutics like Bebtelovimab that target more conserved epitopes (NIH, 2022). Structural studies have shown that BA.2 RBD mutations induce remodeling of the domain, resulting in tighter packing and improved thermostability compared to earlier variants (NIH, 2022). These adaptations facilitate more efficient host cell entry and contribute to the variant's ability to outcompete previous strains (NIH, 2022). Consequently, the RBD remains a focal point for monitoring viral evolution and designing broad-spectrum antiviral strategies (NIH, 2022).

Other names

BA.2 RBDOmicron BA.2 Spike RBDSARS-CoV-2 B.1.1.529.2 RBDSpike protein S1 subunit RBD

Neutralization of the virus by blocking the interaction between the spike protein RBD and the host ACE2 receptor, thereby preventing viral entry into host cells (NIH, 2022).