Coronavirus disease 2019 (COVID-19), formerly known as 2019-nCoV acute respiratory disease, is an infectious disease caused by a beta coronavirus called SARS-CoV-2, a virus closely related to the SARS virus. The first cases appeared in Wuhan, China in December 2019. SARS-CoV-2 genome codes for 4 structural proteins (S, E, M and N) and 2 non-structural proteins (pp1a and pp1b). The structural proteins consist of the following: a Spike protein (S), a membrane glycoprotein (M), an envelope protein (E), a nucleocapsid protein (N) and RNA. 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. It also mediates the fusion of host and viral cell membrane, allowing the virus to enter human cells and begin infection. The spike protein is the major target for neutralizing antibodies and vaccine development. The Spike protein is cleaved off in S1 that interacts with ACE2 and S2 that has the membrane fusion properties. S1 protein corresponds to aa13-685 of Spike protein (1273 aa).