Model for the structure of the putative SARS-CoV-2 transmembrane ion channel dimer ORF3A at 2.1 ├Е
PHOTO: NAT. STRUCT. MOL. BIOL. 10.1038/S41594-021-00619-0 (2021).
In the battle against COVID-19, attention has focused on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein, which initiates viral entry into host cells, and on viral proteins directly involved in replication. However, other viral proteins also play a role in pathogenicity and are potential drug targets. Kern et al. focused on ORF3A, a transmembrane protein that is implicated in apoptosis and inhibition of autophagy and may form an ion channel. The authors used electron microscopy to determine the structure of a dimer at 2.1-angstrom resolution. Although a polar cavity extends from the cytoplasm into the membrane, conformational changes would be required to open a conduction pathway across the membrane. In liposomes, SARS-CoV-2 3a has a non selective cation channel activity that is blocked by polycation channel inhibitors.
Nat. Struct. Mol. Biol. 10.1038/s41594-021-00619-0 (2021).