Protein Domain : Pyocin S killer protein IPR003060

Type	Family
Description	Pyocins are polypeptide toxins produced by, and active against, bacteria. S-type pyocins cause cell death by DNA breakdown due to endonuclease activity [ ]. Pyocins S1 and S2 are S-type bacteriocins of Pseudomonas aeruginosa with different receptor recognition specificities []. The genetic determinants of these pyocins have been cloned from the NIH-H and PAO chromosomes of P. aeruginosa. The determinants each constitute an operon that encodes two proteins of molecular weight 65,600 and 10,000 (pyocin S1) or 74,000 and 10,000 (pyocin S2) with a characteristic sequence (P box), a possible regulatory element involved in the induction of pyocin production, in the 5' upstream region []. These pyocins have almost identical sequences, except in the N-terminal portions of the large proteins, which are substantially different. This similarity suggests that S1 and S2 pyocins, like pyocin AP41, originated from a common ancestor of the E2 group colicins. Purified pyocins S1 and S2 constitute a complex of the two proteins. Both pyocins cause breakdown of chromosomal DNA and complete inhibition of lipid synthesis in sensitive cells. The large protein (not the complex), shows in vitroDNase activity. This activity is inhibited by the small protein of either pyocin [ ].
Short Name	Pyocin_killer