SARS-CoV-2 Spike Reagents

Coronavirus invades cells through spike (S) glycoproteins, a class I fusion protein. It is the major viral surface protein that coronavirus uses to bind to the human cell surface receptor. The S protein also mediates the fusion of the host and viral cell membranes. This allows the virus to enter human cells and begin infection (1).

The spike protein is the major target for neutralizing antibodies and vaccine development (2). The protein modeling suggests that there is a strong interaction between the spike protein receptor-binding domain and its host receptor angiotensin-converting enzyme 2 (ACE2), which regulates both the cross-species and human-to-human transmissions of COVID-19 (3). A recent study has shown that the SARS-CoV-2 spike protein binds ACE2 with a higher affinity than SARS-CoV spike protein (4).

The spike protein in SARS-CoV-2 is heavily glycosylated. Therefore, it utilizes an N-terminal signal sequence to gain access to the ER, and mediate attachment to host receptors. It is the largest structure and makes distinct spikes on the surface of the virus.

For SARS-CoV-2, S protein is cleaved by cellular furin-like protease TMPRSS2 into two separate polypeptides S1 and S2. S1 also consists of a receptor-binding domain (RBD) which binds to the virus ACE2 receptor.