Bacteria killing their own kind: novel bacteriocins of Pseudomonas and other γ-proteobacteria

Pseudomonas aeruginosa strains frequently produce proteinaceous, narrow-spectrum antibacterial bacteriocins known as pyocins. The majority of these compounds exert their toxicity through non-specific DNA degradation inside sensitive cells. Here, we describe the identification of novel bacteriocins of different types in related bacteria inhabiting diverse niches. The abundance of bacteriocin genes in bacteria such as Pseudomonas , Klebsiella and Photorhabdus suggests that these systems play an important role in the competition between rival bacteria. The chimeric nature of these proteins implies that extensive domain swapping has contributed to the diversification of bacteriocins in γ-proteobacteria.