SARS-CoV-2 Envelope: Proteins and Enzymes

The SARS-CoV-2 Envelope protein is one of the four major structural proteins of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19 (1). The envelope protein is the smallest of the four structural proteins, which also includes the membrane protein, spike protein, and nucleocapsid protein (1,2). The envelope protein is synthesized as a 75 amino acid protein with a theoretical molecular weight of approximately 8.4 kDa (2,3). Furthermore, the envelope protein of SARS-CoV-2 has 94.7% sequence identity and 97.4% sequence similarity to the envelope protein of SARS-CoV (2). Structurally, the envelope protein is a membrane protein with a N-terminal domain, an alpha-helical transmembrane domain, and a hydrophilic C-terminal domain (1,4). The envelope protein has multiple functions in viral replication including viral assembly, release, and pathogenesis (2,4). Additionally, the SARS-CoV-2 envelope protein has ion channel activity and functions as a viroporin with a role in virion trafficking (2,4). Coronaviruses lacking the envelope protein are shown to have reduced viral titer and slowed or defective maturation, indicative of a role in virus production and growth (4).

References

1. Malik Y. A. (2020). Properties of Coronavirus and SARS-CoV-2. The Malaysian Journal of Pathology.

2. Yoshimoto F. K. (2020). The Proteins of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2 or n-COV19), the Cause of COVID-19. The Protein Journal. https://doi.org/10.1007/s10930-020-09901-4

3. Uniprot (P0DTC4)

4. J Alsaadi, E. A., & Jones, I. M. (2019). Membrane binding proteins of coronaviruses. Future Virology. https://doi.org/10.2217/fvl-2018-0144