What is "exosortase"

Exosortase refers to a family of integral membrane proteins that occur in Gram-negative bacteria and that recognize and cleave the carboxyl-terminal sorting signal PEP-CTERM. The name derives from a predicted role analogous to sortase, despite the lack any detectable sequence homology, and a strong associate of exosortase genes with exopolysaccharide or extracellular polymeric substance biosynthesis loci. Some archaea have an archaeosortase, related to exosortase rather than to sortases. Archaeosortase A recognizes the signal PGF-CTERM, found at the C-terminus of some archaeal S-layer proteins.