SARS CoV2 antigen S S1 RBD N protein mutant

The SARS-CoV-2 genomic RNA has approximately 30 kb in size and is made up of 13–15 (12 functional) open reading frames (ORFs). The first ORF from the 5′ end comprises approximately 67% of the genome and encodes several non-structural proteins. On the other hand, the remaining ORFs encode both accessory and structural proteins, including the major S, E, M, and N proteins. The S glycoprotein is a trimeric fusion viral protein comprised of two subunits: S1（responsible for receptor binding） and S2 （responsible for membrane fusion）. The S1 subunit is made up of signal peptide, N-terminal domain (NTD) and a receptor-binding domain (RBD). The S2 subunit contains two heptad-repeat regions known as HR-N and HR-C, which form the coiled-coil structures surrounded by the protein ectodomain. Importantly, the S protein in its native form is coated with polysaccharide molecules, a property that partly enables SARS-CoV-2 to evade surveillance of the host immune system during entry.