SARS-CoV-2 Envelope and Membrane Reagents

Upon the entry of SARS-CoV-2 into host cells, from the full-length genomic RNA (29,903 nt) that serves as an mRNA, the first set of viral proteins are translated from the long (>21 kb) open reading frame ORF1ab (1).

The ORF1ab-encoded polyprotein is subsequently processed into 16 individual non-structural proteins (NSP) by two proteases PLpro/nsp3 and 3CLpro/nsp5. The 3’ half of ORF1ab, ORF1b, encodes a variety of enzymes critical for viral transcription and replication (1). In addition to the genomic RNA, nine major sub-genomic RNAs are produced (1). ORF1a and ORF1b are also separately translated and, as in all coronaviruses, translation of ORF1b in SARS-CoV-2 requires a programmed -1 ribosomal frameshift (-1 PRF) (2).

The genome RNA is packaged by the structural proteins to assemble progeny virions. The shorter sub-genomic RNAs encode conserved structural proteins spike protein (S), an envelope protein (E), membrane protein (M) and nucleocapsid protein (N), and several accessory proteins. SARS-CoV-2 is known to have at least 6 accessory proteins (ORFs 3a, 7, 7a, 7b, 8, and 10)

ProSci Incorporated offers antibodies and recombinant proteins representing most of the SARS-CoV-2 proteome. Below is a list of SARS-CoV-2 envelope and membrane reagents to serve as tools for your research needs!

The Envelope and Membrane Proteins (E, M)

The envelope protein is found in small quantities within the virus. It is most likely a transmembrane protein and with ion channel activity. The protein facilitates the assembly and release of the virus and has other functions such as ion channel activity. It is not necessary for viral replication but it is for pathogenesis.

The membrane protein is the most abundant structural protein. It does not contain a signal sequence and exists as a dimer in the virion. It may have two different conformations to enable it to promote membrane curvature as well as bind to nucleocapsid.

References

• 1. D. Kim et al (2020) Cell 181, 125-130
• 2. Y. Sun et al (2021) PNAS 118 No. 26, 20223051118 (https://doi.org/10.1073/pnas. 20223051118)