Fig. 4.

Furin protease binding pocket. (A) Active site region of furin protease. Labels S1, S2, S3, S4, and S5 are regions within the active site where active ligands are supposed to occupy. Regions S1 and S2 are areas where catalytic triad Ser368 (green), His194 (yellow), and Asp153 (purple) are found, and these were areas most occupied by potential inhibitors. (B) The active site catalytic triad are rendered in sticks representation