Spike S2 Subunit: Proteins and Enzymes

Spike S2 subunit contains the C-terminal region of the coronavirus Spike protein. It contains two heptad repeat domains, HR1 and HR2, that interact to form a six-helix bundle bringing the viral membrane close to the host cell membrane allowing fusion to occur. Inhibitors that block this process have therapeutic potential and are currently being studied. In addition to the heptad repeats, there is a C-terminal transmembrane domain responsible for anchoring the Spike protein in the viral membrane and a short cytoplasmic tail.