Pyocine
Pyocins are poisons from the group of bacteriocins that act against the bacterium Pseudomonas aeruginosa . R- and F-type pyocins are similar to the tails of bacteriophages , S-type pyocins are similar to the colicins in E. coli . Pyocins are produced by Pseudomonas aeruginosa to kill closely related Pseudomonas strains.
Word origin
François Jacob discovered and named pyocins after Pseudomonas pyocyanea , in which they were first discovered. The wording is therefore analogous to colicins of E. coli .
S-type pyocins
The S of the S-type pyocins is derived from the English word "soluble" (German: soluble). S-type pyocins are proteinase- sensitive proteins that weigh between 20 and 60 kDa . They are similar to the colicins in E. coli , but in contrast to colicin genes , their genes are chromosomal, not plasmid-coded. They have a modular structure consisting of three domains each: an R (receptor binding), T (translocation) and C (cytotoxic) domain. The R-domain binds a receptor on the cell surface of the target bacterium and thereby creates the specificity of the poison. The T domain enables the pyocin to be transported through the outer membrane into the periplasm . The C-domain is responsible for the cytotoxic effect and can, for example, have nuclease (DNase, tRNase, mRNase) or pore-forming activity.
Many S-type pyocins have been discovered using in-silico methods, but so far only a few of these pyocins have been proven to be functional bacteriocins . The S-type pyocins tested and confirmed in vitro are pyocin S1, SD1, S2, SD2, S3, SD3, AP4, S5, S6, pyocin S8 and PaeM, also called pyocin M1. Pyocin L1 was also examined.
| receptor | C domain | |
|---|---|---|
| AP41 | ? | DNase |
| M1 | ? | Lipid-II breakdown |
| S1 | ? | DNase |
| S2 | FpvAI | DNase |
| S3 | FpvAII | DNase |
| S4 | FpvAI | tRNase |
| S5 | FptA | pore |
| S6 | ? | rRNase |
| S8 | ? | DNase |
| SD1 | ? | tRNase |
| SD2 | FpvAI | tRNase |
| SD3 | FpvAII | tRNase |
| L1 | LPS | ? |
The SD pyocins are naturally occurring chimera made up of the T and R domains of pyocin S1, S2 or S3, and the C domain of colicin D. Pyocine SD2 and SD3 were also called pyocin S11 and S12 prior to their experimental confirmation. Like the SD Pyocine, Pyocin S6 has the same T and R domains as Pyocin S1, but a different C domain.
Immunity proteins
Many S-type pyocins are co-expressed with an immunity gene . The immunity genes of the nucleases are encoded on the same strand as the pyocin. The immunity gene binds the nuclease in order to inactivate it and thereby protect the producing bacterium. Immunity protein and nuclease are released together as a heterodimer . It is believed that the immunity protein is left behind upon entering the target cell. The immunity proteins of pore-forming pyocins are encoded on the opposite DNA strand to the pyocin gene. The immunity proteins of the pore-forming pyocins are not released with the pyocin. It is believed that the immunity protein resides in the inner membrane of the producing cell and prevents pore formation by the pyocin.
R-type pyocine
The structure of R- and T-type pyocins corresponds to that of the tail piece of bacteriophage. A collective term for R- and F-type bacteriocins is therefore tailocine, derived from tail for tail. They have a telescope architecture that allows target bacteria to pierce the outer membrane. In contrast to the inner core, the outer sheath can contract upon contact with the target cell. As a result, the core pushes through the outer membrane. As with bacteriophages , the specificity of the R-type pyocins is given by tail fibers that extend from a base plate.
So far, pyocin R1, R2, R3, R4, R5, C9, 21 and 430c have been investigated.
F-type pyocins
F-type pyocins are rod-shaped and flexible. The core is 106 nm long, 10 nm in diameter and non-contractible. As with R-type pyocins, the specificity is given by fibers that interact with the target cells. Pyocin F1, F2, F3 and pyocin 28 have long been investigated.
Physiological function
In ecological environments such as topsoil and plants, pyocins play an important role in the defense of ecological niches. When a host organism is infected, bacteriocins can help both the infecting bacteria in conquering ecological niches (displacement of the host microbiome) and the host microbiome in defending their ecological niches. The maintenance of bacteriocin genes and their expression is only beneficial in structured habitats. In unstructured habitats (e.g. liquid culture media), bacteria that produce bacteriocins are displaced by faster growth by bacteria that only produce immunity proteins against bacteriocins.
application
The use of pyocins of all three types as specific antibiotics is discussed. The advantage would be the specific effect on one or a few bacterial strains, which leave the rest of the microbiome intact and thus avoid dysbioses .
literature
Probably the most cited and clearest review article about pyocins is The Pyocins of Pseudomonas Aeruginosa . The most up-to-date and detailed review article on pyocins is Ribosomally Encoded Antibacterial Proteins and Peptides from Pseudomonas.
Individual evidence
- ↑ François Jacob: biosynthesis Induite et Mode D'action D'une Pyocine, antibiotique de Pseudomonas pyocyanea , Ann. Inst. Pasteur, 86 (1954), 149-160.
- ↑ a b c d e Yvon Michel-Briand, Christine Baysse: The pyocins of Pseudomonas aeruginosa. In: Biochemistry. 84, 2002, p. 499, doi : 10.1016 / S0300-9084 (02) 01422-0 .
- ↑ a b c Maarten GK Ghequire, René De Mot: Efficacy of species-specific protein antibiotics in a murine model of acute Pseudomonas aeruginosa lung infection. In: FEMS Microbiology Reviews. 38, 2014, p. 523, doi : 10.1111 / 1574-6976.12079 .
- ^ A b Y. Sano, H. Matsui, M. Kobayashi, M. Kageyama: Molecular structures and functions of pyocins S1 and S2 in Pseudomonas aeruginosa. In: Journal of bacteriology. Volume 175, Number 10, May 1993, pp. 2907-2916, PMID 8491711 , PMC 204608 (free full text).
- ↑ a b c L. C. McCaughey, I. Josts u. a .: Discovery, characterization and in vivo activity of pyocin SD2, a protein antibiotic from Pseudomonas aeruginosa. In: Biochemical Journal. 473, 2016, p. 2345, doi : 10.1042 / BCJ20160470 .
- ↑ C. Duport, C. Baysse, Y. Michel-Briand: Molecular characterization of pyocin S3, a novel S-type pyocin from Pseudomonas aeruginosa. In: The Journal of biological chemistry. Volume 270, Number 15, April 1995, pp. 8920-8927, PMID 7721800 .
- ^ Y. Sano: The inherent DNase of pyocin AP41 causes breakdown of chromosomal DNA. In: Journal of bacteriology. Volume 175, Number 3, February 1993, pp. 912-915, PMID 8423163 , PMC 196246 (free full text).
- ↑ H. Ling, N. Saeidi, BH Rasouliha, MW Chang: A predicted S-type pyocin shows a bactericidal activity against clinical Pseudomonas aeruginosa isolates through membrane damage. In: FEBS letters. Volume 584, Number 15, August 2010, pp. 3354-3358, doi : 10.1016 / j.febslet.2010.06.021 , PMID 20580355 .
- ↑ J. Dingemans, MG Ghequire, M. Craggs, R. De Mot, P. Cornelis: Identification and functional analysis of a bacteriocin, pyocin S6, with ribonuclease activity from a Pseudomonas aeruginosa cystic fibrosis clinical isolate. In: MicrobiologyOpen. Volume 5, Number 3, June 2016, pp. 413-423, doi : 10.1002 / mbo3.339 , PMID 26860427 , PMC 4905994 (free full text).
- ↑ https://www.ncbi.nlm.nih.gov/pubmed/?term=pyocin%20s8
- ↑ H. Barreteau, A. Bouhss, M. Fourgeaud, JL Mainardi, T. Touzé, F. Gérard, D. Blanot, M. Arthur, D. Mengin-Lecreulx: Human- and plant-pathogenic Pseudomonas species produce bacteriocins exhibiting colicin M-like hydrolase activity towards peptidoglycan precursors. In: Journal of bacteriology. Volume 191, Number 11, June 2009, pp. 3657-3664, doi : 10.1128 / JB.01824-08 , PMID 19346308 , PMC 2681890 (free full text).
- ↑ Bahareh Haji Rasouliha, Hua Ling u. a .: A Predicted Immunity Protein Confers Resistance to Pyocin S5 in a Sensitive Strain of Pseudomonas aeruginosa. In: ChemBioChem. 14, 2013, p. 2444, doi : 10.1002 / cbic.201300410 .
- ↑ Ylaine Gerardin, Michael Springer, Roy Kishony: A competitive trade-off limits the selective advantage of increased antibiotic production. In: Nature Microbiology. 1, 2016, p. 16175, doi : 10.1038 / nmicrobiol.2016.175 .
- ↑ Laura C. McCaughey, Neil. D. Ritchie, Gillian R. Douce, Thomas J. Evans, Daniel Walker: Efficacy of species-specific protein antibiotics in a murine model of acute Pseudomonas aeruginosa lung infection. In: Scientific Reports. 6, 2016, doi : 10.1038 / srep30201 .