Description | The CoV Spike (S) protein is an envelope glycoprotein that plays the most important role in viral attachment, fusion, and entry into host cells, and serves as a major target for the development of neutralizing antibodies, inhibitors of viral entry, and vaccines. It is synthesised as a precursor protein that is cleaved into an N-terminal S1 subunit (~700 amino acids) and a C-terminal S2 subunit (~600 amino acids) that mediates attachment and membrane fusion, respectively. Three S1/S2 heterodimers assemble to form a trimer spike protruding from the viral envelope. The S1 subunit contains a receptor-binding domain (RBD), while the S2 subunit contains a hydrophobic fusion peptide and two heptad repeat regions. S1 contains two structurally independent domains, the N-terminal domain (NTD) and the C-terminal domain (C-domain). Depending on the virus, either the NTD or the C-domain can serve as the receptor-binding domain (RBD). Most CoVs, including SARS-CoV-2, SARS-CoV, and MERS-CoV use the C-domain to bind their receptors. However, CoV such as mouse hepatitis virus (MHV) uses the NTD to bind its receptor, mouse carcinoembryonic antigen related cell adhesion molecule 1a (mCEACAM1a). The S1 NTD contributes to the Spike trimer interface [, , , ].This is the receptor-binding domain (RBD) of Spike protein S1 subunit from SARS-CoV which binds the extracellular peptidase domain of angiotensin-converting enzyme 2 (ACE2). It has been shown that the receptor binding induces the dissociation of the S1 with ACE2, prompting the S2 to transit from a metastable pre-fusion to a more-stable post-fusion state that is essential for membrane fusion [ , ]. | Name | Spike (S) protein S1 subunit, receptor-binding domain, SARS-CoV |
Short Name | Spike_S1_RBD_SARS-CoV | Type | Domain |