COVID Spike Protein

Description

Molecular image from the RCSB Protein Data Bank, file 6VSB. **Pale yellow** = S1 domain (attaches to the ACE2 target cell receptor). **Green** = Stem domain (S2), which unfolds upon activation to embed transmembrane regions into the membrane of the target cell. **Red** = domain that is removed by two cuts from the target cell protease (membrane protease). **Magenta** = site of the first cut, which releases the S1 domain, which is attached to the ACE2 receptor. **Organge-yellow** = (between red & green regions) site of the second cut, which activates the hinged fusion protein extended conformation. **Blue** = Fusion protein domain (embeds into the target cell membrane).