title: Structure and Function of the PiuA and PirA Siderophore-Drug Receptors from Pseudomonas aeruginosa and Acinetobacter baumannii.
abstract: The outer membrane of Gram-negative bacteria presents an efficient barrier to the permeation of antimicrobial molecules. One strategy pursued to circumvent this obstacle is to hijack transport systems for essential nutrients, such as iron. BAL30072 and MC-1 are two monobactams conjugated to a dihydroxypyridone siderophore that are active againstPseudomonas aeruginosaandAcinetobacter baumanniiHere, we investigated the mechanism of action of these molecules inA. baumanniiWe identified two novel TonB-dependent receptors, termedAb-PiuA andAb-PirA, that are required for the antimicrobial activity of both agents. Deletion of eitherpiuAorpirAinA. baumanniiresulted in 4- to 8-fold-decreased susceptibility, while their overexpression in the heterologous hostP. aeruginosaincreased susceptibility to the two siderophore-drug conjugates by 4- to 32-fold. The crystal structures of PiuA and PirA fromA. baumanniiand their orthologues fromP. aeruginosawere determined. The structures revealed similar architectures; however, structural differences between PirA and PiuA point to potential differences between their cognate siderophore ligands. Spontaneous mutants, selected upon exposure to BAL30072, harbored frameshift mutations in either the ExbD3 or the TonB3 protein ofA. baumannii, forming the cytoplasmic-membrane complex providing the energy for the siderophore translocation process. The results of this study provide insight for the rational design of novel siderophore-drug conjugates against problematic Gram-negative pathogens.
authors.affiliation: Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom.
authors.forename: Lucile
authors.initials: L
authors.lastname: Moynié
authors.affiliation: Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland.|Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Luscher
authors.affiliation: Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland.|ISGlobal, CRESIB, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Dora
authors.initials: D
authors.lastname: Rolo
authors.affiliation: Jacobs University, Bremen, Germany.
authors.forename: Daniel
authors.identifier: 0000-0001-5750-7505
authors.initials: D
authors.lastname: Pletzer
authors.affiliation: Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom.
authors.forename: Antoni
authors.initials: A
authors.lastname: Tortajada
authors.affiliation: Jacobs University, Bremen, Germany.
authors.forename: Helge
authors.initials: H
authors.lastname: Weingart
authors.affiliation: Jacobs University, Bremen, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Braun
authors.affiliation: Basilea Pharmaceutica International Ltd., Basel, Switzerland.
authors.forename: Malcolm G P
authors.initials: MG
authors.lastname: Page
authors.affiliation: Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom.
authors.forename: James H
authors.initials: JH
authors.lastname: Naismith
authors.affiliation: Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland thilo.kohler@unige.ch.|Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Thilo
authors.initials: T
authors.lastname: Köhler
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008997:Monobactams / Q000494:pharmacology; D009154:Mutation / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D013844:Thiazoles / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; C552042:BAL 30072; D001426:Bacterial Proteins; D008997:Monobactams; D013844:Thiazoles
keywords: Acinetobacter baumannii; Pseudomonas aeruginosa; siderophore-drug receptor