FIGURE 5.

Location of furin variable surface loops in the furin catalytic domain. The murine furin catalytic domain structure (PDB 1P8J) is depicted in ribbons showing the four variable loops surrounding the catalytic cleft in stick representation: loop 187–189 (yellow), loop 298–300 (green), loop 345–350 (cyan), and loop 357–359 (purple). The catalytic triad residues are shown in stick (red). The 298–300 loop lies adjacent to the S2′ binding pocket (29). The figure was prepared using PyMol software.