Fig 5.

Different positions of key R329 residues in the cleavage site. (A to C) Electrostatic diagrams of cleavage sites show that the key R329 residue is far from the negatively charged cavity in H3HA0 (A), R329 covers the negatively charged cavity in 18HA0 (B), and R329 is buried in the negatively charged cavity in H16HA0 (C). (D to F) Detailed interaction between the cleavage site and the negatively charged cavity and adjacent subunit in different HA0s. The cleavage site is colored yellow in H3HA0 (D), orange in 18HA0 (E), and green in H16HA0 (F). The main residues in the negatively charged cavity are colored pink. The hydrogen bonds are shown as black dashed lines.