Involved in protection of the bacterium from thermal and osmotic stresses. The enzyme shows specific recognition of a C-terminal tripeptide, Xaa-Yaa-Zaa, in which Xaa is preferably Ala or Leu, Yaa is preferably Ala or Tyr, and Zaa is preferably Ala, but then cleaves at a variable distance from the C-terminus. A typical cleavage is -Ala-Ala-|-Arg-Ala-Ala-Lys-Glu-Asn-Tyr-Ala-Leu-Ala-Ala. May undergo autocatalytic processing at the C-terminus (398-434 or 425-434 missing). Belongs to the peptidase S41A family.