9.A.33 The Pyocin R2 Phage P2 Tail Fiber Protein (Pyocin R2) Family
Pseudomonas aeruginosa produces R-type pyocins that resemble tail fibers of phage P2. These pyocins resemble contractile but non-flexible tail fiber proteins of phage P2. In fact, pyocin R2 is homologous to P2 phage tail fiber proteins and is derived from an ancestral protein sharing a common origin with it. Pyocin R2 (PRF15) is large (701 aas) and has several (~5) regions that may be sufficiently hydrophobic to pass through the membrane as α-helices (Nakayama et al. 2000).
R-type pyocins cause depolarization of the cytoplasmic membrane of sensitive cells, and they inhibit active transport. These observations are consistent with, but do not prove pore formation.