Skip to main content
. 2022 Mar 2;13:845156. doi: 10.3389/fphys.2022.845156

FIGURE 2.

FIGURE 2

Epidemics Human Coronaviruses (HCoVs) structure of genome. The genomes of epidemics Human CoVs contain a single-stranded, positive-sense RNA ranging of 27–32 kb in size. One third of the genome, expressed at the 3′ terminal, encodes the main proteins of the virus involved in the virus-cell receptor binding and virion activity. In particular, four structural proteins: E: envelope protein, M: membrane protein, N: nucleocapsid protein, S: spike protein. The S protein of HCoVs consists of two subunits, S1 and S2. S1 subunit consist of a C-Terminal Domain (CTD) – also named Receptor Binding Domain (RBD) – and a N-Terminal Domain (NTD). S2 subunit contains a fusion peptide (FP), transmembrane domain (TM) region, heptad repeat 1-2 (HR1, HR2). SP, signal peptide; CP, cytoplasmic peptide; ORF, open reading frame (Modified by Zhao et al., 2020b).