title: Retargeting R-type pyocins to generate novel bactericidal protein complexes.
abstract: R-type pyocins are high-molecular-weight bacteriocins that resemble bacteriophage tail structures and are produced by some Pseudomonas aeruginosa strains. R-type pyocins kill by dissipating the bacterial membrane potential after binding. The high-potency, single-hit bactericidal kinetics of R-type pyocins suggest that they could be effective antimicrobials. However, the limited antibacterial spectra of natural R-type pyocins would ultimately compromise their clinical utility. The spectra of these protein complexes are determined in large part by their tail fibers. By replacing the pyocin tail fibers with tail fibers of Pseudomonas phage PS17, we changed the bactericidal specificity of R2 pyocin particles to a different subset of P. aeruginosa strains, including some resistant to PS17 phage. We further extended this idea by fusing parts of R2 tail fibers with parts of tail fibers from phages that infect other bacteria, including Escherichia coli and Yersinia pestis, changing the killing spectrum of pyocins from P. aeruginosa to the bacterial genus, species, or strain that serves as a host for the donor phage. The assembly of active R-type pyocins requires chaperones specific for the C-terminal portion of the tail fiber. Natural and retargeted R-type pyocins exhibit narrow bactericidal spectra and thus can be expected to cause little collateral damage to the healthy microbiotae and not to promote the horizontal spread of multidrug resistance among bacteria. Engineered R-type pyocins may offer a novel alternative to traditional antibiotics in some infections.
authors.affiliation: AvidBiotics Corporation, 385 Oyster Point Blvd., Suite 6A, South San Francisco, CA 94080, USA.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Williams
authors.forename: Dana
authors.initials: D
authors.lastname: Gebhart
authors.forename: David W
authors.initials: DW
authors.lastname: Martin
authors.forename: Dean
authors.initials: D
authors.lastname: Scholl
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D019677:Artificial Gene Fusion; D001435:Bacteriophages / Q000235:genetics; D003090:Coliphages / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000821:virology; D008969:Molecular Sequence Data; D017105:Pseudomonas Phages / Q000235:genetics*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000821:virology*; D011709:Pyocins / Q000494:pharmacology*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D015010:Yersinia pestis / Q000187:drug effects / Q000821:virology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D011709:Pyocins; D011993:Recombinant Fusion Proteins