Figure 1: Structure of SARS-CoV-2
Schematic representation of the genome organization and functional domains of SARS-CoV-2. The single-stranded RNA genomes of SARS-CoV and SARS-CoV-2 encode two large genes, the ORF1a and ORF1b genes. ORF1a/b (2/3 of the SARS-CoV-2 genome) in the 5′-terminal encodes polyproteins, which form the viral replicase-transcriptase complex. The other ORFs encode four main structural proteins: spike protein (S), envelope protein (E), nucleocapsid protein (N) and membrane protein (M), as well as accessory proteins.