The Structural Differences between SARS‐CoV‐2 and SARS‐CoV‐1 Spike Proteins

Cetin, Sena; Ng, Sydney; Zunino, Marzia

COVID‐19 is a highly infectious disease that mainly affects the human respiratory system. Since its emergence, SARS‐CoV‐2 has resulted in over 86.7 million cases and over 1.87 million deaths worldwide (WHO Coronavirus Disease (COVID‐19) Dashboard). Coronavirus spike glycoproteins assist in entry and infection of cells by binding to the human ACE2 receptor. Because of this, they are the main target for antibodies and inhibitors (Walls et al., 2020). There are many different strains of coronavirus, including SARS‐CoV‐1 and SARS‐CoV‐2. Although these are both β‐coronaviruses that bind to the ACE2 receptor through a spike protein, SARS‐CoV‐2 has been found to be less deadly but more easily transmissible than SARS‐CoV‐1 (Fani et al., 2020). We hypothesized that the variations in the structure of the spike proteins in different strains cause these different characteristics. In order to understand the structural differences between SARS‐CoV‐2 and SARS‐CoV‐1 spike proteins, we compared their structures by aligning them using PyMOL, a molecular visualization system. We observed that the receptor binding domain (RBD) of the spike proteins have differences in their structure. We will study these to identify their significance. The structure of a protein is directly related to its function which is why we think that this investigation is crucial to understanding COVID‐19. We expect that these regions are important for specific drug targets for SARS‐CoV‐2.