SARS-CoV-2 Omicron XBB.1.5 spike protein receptor-binding domain (XBB.1.5 RBD)

The SARS-CoV-2 Omicron XBB.1.5 spike protein receptor-binding domain (RBD) is a critical component of the viral envelope that mediates infection by binding to the human angiotensin-converting enzyme 2 (ACE2) receptor [1, 3]. XBB.1.5, colloquially known as the 'Kraken' variant, is a recombinant sublineage of Omicron that features a key F486P mutation in the RBD, which significantly enhances its binding affinity for ACE2 compared to previous variants [12, 14]. This interaction surface is the primary target for neutralizing antibodies elicited by both natural infection and vaccination [15, 18]. Due to its extensive mutational profile, XBB.1.5 exhibits profound immune evasion, rendering many early therapeutic monoclonal antibodies ineffective [2, 25]. Consequently, updated monovalent vaccines and newer monoclonal antibodies like pemivibart have been developed to specifically target this domain [19, 21, 30]. Monitoring the structural evolution of this interaction surface is essential for maintaining the efficacy of COVID-19 countermeasures [4, 8]. Therapeutic strategies focus on blocking the RBD-ACE2 interface to prevent viral entry into host cells [10, 13].

Other names

XBB.1.5 SpikeKraken variant RBDSARS-CoV-2 S protein RBD (XBB.1.5)SARS-CoV-2 Omicron XBB.1.5 receptor-binding motif

Neutralization of viral entry by blocking the interaction between the spike protein receptor-binding domain and the host ACE2 receptor.