SARS-CoV-2 Ligands Database

The fusion peptide (FP) is a short hydrophobic region located near the N-terminus of the S2 subunit of the spike protein. Its primary role is to facilitate the fusion of the viral membrane with the host cell membrane. When the virus is ready to enter the host cell, the fusion peptide is exposed and inserts itself into the host membrane, initiating the fusion process.

Heptad Repeat 1 (HP1) is a region that contains repeating patterns of seven amino acids (hence "heptad"). This region is also located within the S2 subunit of the spike protein. HR1 is critical for the formation of the six-helix bundle structure that stabilizes the fusion process. It plays a key role in bringing the viral and host membranes close together, allowing for fusion to occur.