This the C-terminal activator domain of pesticin, a hydrolase enzyme secreted by Yersinia pestis and other Gammaproteobacteria to kill related bacteria occupying the same ecological niche. It is referred to as a bacteriocin and it leads to the hydrolysis of peptidoglycan. Its immunity protein is Pim. Pesticin carries an elongated N-terminal translocation domain, an intermediate receptor binding domain, and a C-terminal activity domain with structural analogy to lysozyme homologues. The full-length protein is toxic to bacteria when taken up to the target site via the outer or the inner membrane. The receptor domain is necessary for the close contact with the outer membrane; the N-terminal is a type of translocational, TonB box; the C-terminal domain is the death-delivering domain [1].

1: Structural and mechanistic studies of pesticin, a bacterial homolog of phage lysozymes. Patzer SI, Albrecht R, Braun V, Zeth K; J Biol Chem. 2012;287:23381-23396. PMID:22593569