May play a dual role in regulation of ESX-1 secretion and virulence. Acts as a protease that cleaves EspB. Cell wall-associated. The N-terminal extension wraps intimately around the catalytic domain where, tethered by a disulfide bond, it forms additional interactions with a unique extended loop that protrudes from the catalytic core. It might contribute to the conformational stability of the active site cleft and surrounding regions. Deletion mutant fails to secrete EsxA. Belongs to the peptidase S8 family.