Acts as a processive, ATP-dependent zinc metallopeptidase for both cytoplasmic and membrane proteins. Plays a role in the quality control of integral membrane proteins. Binds 1 zinc ion per subunit. Homohexamer. Expressed at a low constitutive level, expression is increased after exposure to 42 degrees Celsius. Transcription is partially repressed by CtsR. Cells grow more slowly under optimal conditions, and much mre slowly at 42 degrees Celsius. In the central section; belongs to the AAA ATPase family. In the C-terminal section; belongs to the peptidase M41 family.