title: Discovery, characterization and in vivo activity of pyocin SD2, a protein antibiotic from Pseudomonas aeruginosa.
abstract: Increasing rates of antibiotic resistance among Gram-negative pathogens such as Pseudomonas aeruginosa means alternative approaches to antibiotic development are urgently required. Pyocins, produced by P. aeruginosa for intraspecies competition, are highly potent protein antibiotics known to actively translocate across the outer membrane of P. aeruginosa. Understanding and exploiting the mechanisms by which pyocins target, penetrate and kill P. aeruginosa is a promising approach to antibiotic development. In this work we show the therapeutic potential of a newly identified tRNase pyocin, pyocin SD2, by demonstrating its activity in vivo in a murine model of P. aeruginosa lung infection. In addition, we propose a mechanism of cell targeting and translocation for pyocin SD2 across the P. aeruginosa outer membrane. Pyocin SD2 is concentrated at the cell surface, via binding to the common polysaccharide antigen (CPA) of P. aeruginosa lipopolysaccharide (LPS), from where it can efficiently locate its outer membrane receptor FpvAI. This strategy of utilizing both the CPA and a protein receptor for cell targeting is common among pyocins as we show that pyocins S2, S5 and SD3 also bind to the CPA. Additional data indicate a key role for an unstructured N-terminal region of pyocin SD2 in the subsequent translocation of the pyocin into the cell. These results greatly improve our understanding of how pyocins target and translocate across the outer membrane of P. aeruginosa. This knowledge could be useful for the development of novel anti-pseudomonal therapeutics and will also support the development of pyocin SD2 as a therapeutic in its own right.
authors.affiliation: The Ithree Institute, University of Technology Sydney, Ultimo, New South Wales 2007, Australia Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, U.K. Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, U.K. Laura.mccaughey@uts.edu.au daniel.walker@glasgow.ac.uk.
authors.forename: Laura C
authors.initials: LC
authors.lastname: McCaughey
authors.affiliation: Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, U.K.
authors.forename: Inokentijs
authors.initials: I
authors.lastname: Josts
authors.affiliation: Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, U.K.
authors.forename: Rhys
authors.initials: R
authors.lastname: Grinter
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, U.K.
authors.forename: Paul
authors.initials: P
authors.lastname: White
authors.affiliation: School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, U.K.
authors.forename: Olwyn
authors.initials: O
authors.lastname: Byron
authors.affiliation: Strathclyde Institute for Pharmaceutical and Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, U.K.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Tucker
authors.affiliation: School of Molecular Bioscience, University of Sydney, New South Wales 2008, Australia.
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Matthews
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, U.K.
authors.forename: Colin
authors.initials: C
authors.lastname: Kleanthous
authors.affiliation: The Ithree Institute, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Whitchurch
authors.affiliation: Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, U.K. Laura.mccaughey@uts.edu.au daniel.walker@glasgow.ac.uk.
authors.forename: Daniel
authors.initials: D
authors.lastname: Walker
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002942:Circular Dichroism; D003001:Cloning, Molecular; D008171:Lung Diseases / Q000188:drug therapy; D051379:Mice; D011550:Pseudomonas aeruginosa / Q000737:chemistry*; D011709:Pyocins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D053838:Scattering, Small Angle; D013056:Spectrophotometry, Ultraviolet; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D011709:Pyocins
keywords: Pseudomonas aeruginosa; antibiotics; bacteriocins; common polysaccharide antigen; outer membrane; pyocins