Coronavirus encode five structural proteins in their genomes. These are the Spike (S), Membrane (M), Envelope (E) glycoproteins, Hemaglutinin Esterase (HE) and Nucleocapsid (N) protein. All envelope proteins and N protein is present in all virions but HE is only present in some beta coronaviruses. In adition to that, it is thougt the virus particles are huddled together owing to interaction between these proteins.