The R‐type pyocin of Pseudomonas aeruginosa is related to P2 phage, and the F‐type is related to lambda phage

Abstract

SummaryPseudomonas aeruginosa produces three types of bacteriocins: R-, F-and S-type pyocins. The S-type pyocin is a colicin-like protein, whereas the R-type pyocin resembles a contractile but non-flexible tail structure of bacteriophage, and the F-type a flexible but non-contractile one. As genetically related phages exist for each type, these pyocins have been thought to be variations of defective phage. In the present study, the nucleotide sequence of R2 pyocin genes, along with those for F2 pyocin, which are located downstream of the R2 gene cluster on the chromosome of P. aeruginosa PAO1, was analysed in order to elucidate the relationship between the pyocins and bacteriophages. The results clearly demonstrated that the R-type pyocin is derived from a common ancestral origin with P2 phage and the Ftype from l phage. This notion was supported by identification of a lysis gene cassette similar to those for bacteriophages. The gene organization of the R2 and F2 pyocin gene cluster, however, suggested that both pyocins are not simple defective phages, but are phage tails that have been evolutionarily specialized as bacteriocins. A systematic polymerase chain reaction (PCR) analysis of P. aeruginosa strains that produce various subtypes of R and F pyocins revealed that the genes for every subtype are located between trpE and trpG in the same or very similar gene organization as for R2 and F2 pyocins, but with alterations in genes that determine the receptor specificity.

Genomic diversity of enterohemorrhagic Escherichia coli O157 revealed by whole genome PCR scanning

“…We originally used a systematic PCR analysis, called PCR scanning, to analyze the strain-tostrain difference of the genetic organization of the R͞F pyocin locus on the Pseudomonas aeruginosa chromosome (8). In that analysis, we selected primer target regions with spacing of desired lengths and designed a set of PCR primer pairs so that amplified segments overlapped with adjacent segments at both ends and covered the entire region to be examined.…”

The phage λ major tail protein structure reveals a common evolution for long-tailed phages and the type VI bacterial secretion system

“…Most strains of P. aeruginosa produce phage tail-like entities, known as Pyocins, that are able to selectively kill other P. aeruginosa strains (27). The operons encoding Pyocins are undoubtedly derived from phage genomes, because significant sequence similarity is observed between Pyocin proteins and various phage tail proteins.…”

Cryo‐ EM reconstruction of Type VI secretion system baseplate and sheath distal end

“…Bacteria use phage‐related contractile nanomachines to kill competition or manipulate the surrounding environment (Nakayama et al , 2000; Heymann et al , 2013; Shikuma et al , 2014; Ge et al , 2015). Evolutionarily related Type VI secretion system (T6SS) is used by bacteria to deliver proteins into both bacterial and eukaryotic cells (Mougous et al , 2006; Pukatzki et al , 2006; Hood et al , 2010; MacIntyre et al , 2010; Durand et al , 2014; Ho et al , 2014; Alcoforado Diniz et al , 2015; Hachani et al , 2016).…”

“…Rapid sheath contraction propels the tip complex at the end of the inner tube formed from stacks of Hcp rings into the target cell periplasm or cytosol (Vettiger & Basler, 2016). In contrast to phages and many other contractile nanomachines, which translocate proteins only once by a single sheath contraction (Nakayama et al , 2000; Ge et al , 2015; Hu et al , 2015), the contracted T6SS sheath is disassembled by a cytosolic unfoldase ClpV or ClpB to allow for repeated protein secretion (Bönemann et al , 2009; Pietrosiuk et al , 2011; Basler & Mekalanos, 2012; Basler et al , 2012; Kapitein et al , 2013; Förster et al , 2014; Brodmann et al , 2017). …”