A Natural Chimeric Pseudomonas Bacteriocin with Novel Pore-Forming Activity Parasitizes the Ferrichrome Transporter

Ghequire, M.G.K. ; Kemland, L. ; Anoz-Carbonell, E. (Universidad de Zaragoza) ; Buchanan, S.K. ; De Mot, R.

Resumen: Modular bacteriocins represent a major group of secreted protein toxins with a narrow spectrum of activity, involved in interference competition between Gram-negative bacteria. These antibacterial proteins include a domain for binding to the target cell and a toxin module at the carboxy terminus. Self-inhibition of producers is provided by coexpression of linked immunity genes that transiently inhibit the toxin''s activity through formation of bacteriocin-immunity complexes or by insertion in the inner membrane, depending on the type of toxin module. We demonstrate strain-specific inhibitory activity for PmnH, a Pseudomonas bacteriocin with an unprecedented dual-toxin architecture, hosting both a colicin M domain, potentially interfering with peptidoglycan synthesis, and a novel colicin N-type domain, a pore-forming module distinct from the colicin Ia-type domain in Pseudomonas aeruginosa pyocin S5. A downstream-linked gene product confers PmnH immunity upon susceptible strains. This protein, ImnH, has a transmembrane topology similar to that of Pseudomonas colicin M-like and pore-forming immunity proteins, although homology with either of these is essentially absent. The enhanced killing activity of PmnH under iron-limited growth conditions reflects parasitism of the ferrichrome-type transporter for entry into target cells, a strategy shown here to be used as well by monodomain colicin M-like bacteriocins from pseudomonads. The integration of a second type of toxin module in a bacteriocin gene could offer a competitive advantage against bacteria displaying immunity against only one of both toxic activities.

Idioma: Inglés

DOI: 10.1128/mBio.01961-16

Año: 2017

Publicado en: MBIO 8, 1 (2017), e01961-16
ISSN: 2161-2129

Factor impacto JCR: 6.689 (2017)

Categ. JCR: MICROBIOLOGY rank: 13 / 125 = 0.104 (2017) - Q1 - T1

Factor impacto SCIMAGO: 4.106 - Virology (Q1) - Microbiology (Q1)

Financiación: info:eu-repo/grantAgreement/ES/MEC/Erasmus-800019

Tipo y forma: Article (Published version)

Área (Departamento): Área Bioquímica y Biolog.Mole. (Dpto. Bioq.Biolog.Mol. Celular)