title: Mutation in elongation factor G confers resistance to the antibiotic argyrin in the opportunistic pathogen Pseudomonas aeruginosa.
abstract: The natural myxobacterial product argyrin is a cyclic peptide exhibiting immunosuppressive activity as well as antibacterial activity directed against the highly intrinsically resistant opportunistic pathogen Pseudomonas aeruginosa. In this study, we used whole-genome sequencing technology as a powerful tool to determine the mode of action of argyrin. Sequencing of argyrin-resistant P. aeruginosa isolates selected in vitro uncovered six point mutations that distinguished the resistant mutants from their susceptible parental strain. All six mutations were localized within one gene: fusA1, which encodes for the elongation factor EF-G. After the reintroduction of selected mutations into the susceptible wild type, the strain became resistant to argyrin. Surface plasmon resonance experiments confirmed the interaction of argyrin A with FusA1. Interestingly, EF-G has been previously shown to be the target of the anti-Staphylococcus antibiotic fusidic acid. Mapping of the mutations onto a structural model of EF-G revealed that the mutations conveying resistance against argyrin were clustered within domain III on the side opposite to that involved in fusidic acid binding, thus indicating that argyrin exhibits a new mode of protein synthesis inhibition. Although no mutations causing argyrin resistance have been found in other genes of P. aeruginosa, analysis of the sequence identity in EF-G and its correlation with argyrin resistance in different bacteria imply that additional factors such as uptake of argyrin play a role in the argyrin resistance of other organisms.
authors.affiliation: Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany.
authors.forename: Piotr
authors.initials: P
authors.lastname: Bielecki
authors.forename: Peer
authors.initials: P
authors.lastname: Lukat
authors.forename: Kristina
authors.initials: K
authors.lastname: Hüsecken
authors.forename: Andreas
authors.initials: A
authors.lastname: Dötsch
authors.forename: Heinrich
authors.initials: H
authors.lastname: Steinmetz
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Hartmann
authors.forename: Rolf
authors.initials: R
authors.lastname: Müller
authors.forename: Susanne
authors.initials: S
authors.lastname: Häussler
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects* / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D009154:Mutation; D020653:Peptide Elongation Factor G / Q000235:genetics*; D010456:Peptides, Cyclic / Q000737:chemistry / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics*; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D020653:Peptide Elongation Factor G; D010456:Peptides, Cyclic; C530877:argyrin A