Peptidase S8 family domain in Autotransporter serine proteases
Autotransporter serine proteases belong to Peptidase S8 or Subtilase family. Subtilases, or subtilisin-like serine proteases, have an Asp/His/Ser catalytic triad similar to that found in trypsin-like proteases, but do not share their three-dimensional structure (an example of convergent evolution). Autotransporters are a superfamily of outer membrane/secreted proteins of gram-negative bacteria. The presence of these subtilisin-like domains in these autotransporters are may enable them to be auto-catalytic and may also serve to allow them to act as a maturation protease cleaving other outer membrane proteins at the cell surface.