title: Ferric-pyoverdine recognition by Fpv outer membrane proteins of Pseudomonas protegens Pf-5.
abstract: The soil bacterium Pseudomonas protegens Pf-5 (previously called P. fluorescens Pf-5) produces two siderophores, enantio-pyochelin and a compound in the large and diverse pyoverdine family. Using high-resolution mass spectroscopy, we determined the structure of the pyoverdine produced by Pf-5. In addition to producing its own siderophores, Pf-5 also utilizes ferric complexes of some pyoverdines produced by other strains of Pseudomonas spp. as sources of iron. Previously, phylogenetic analysis of the 45 TonB-dependent outer membrane proteins in Pf-5 indicated that six are in a well-supported clade with ferric-pyoverdine receptors (Fpvs) from other Pseudomonas spp. We used a combination of phylogenetics, bioinformatics, mutagenesis, pyoverdine structural determinations, and cross-feeding bioassays to assign specific ferric-pyoverdine substrates to each of the six Fpvs of Pf-5. We identified at least one ferric-pyoverdine that was taken up by each of the six Fpvs of Pf-5. Functional redundancy of the Pf-5 Fpvs was also apparent, with some ferric-pyoverdines taken up by all mutants with a single Fpv deletion but not by a mutant having deletions in two of the Fpv-encoding genes. Finally, we demonstrated that phylogenetically related Fpvs take up ferric complexes of structurally related pyoverdines, thereby establishing structure-function relationships that can be employed in the future to predict the pyoverdine substrates of Fpvs in other Pseudomonas spp.
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
authors.forename: Sierra L
authors.initials: SL
authors.lastname: Hartney
authors.forename: Sylvie
authors.initials: S
authors.lastname: Mazurier
authors.forename: Maëva K
authors.initials: MK
authors.lastname: Girard
authors.forename: Samina
authors.initials: S
authors.lastname: Mehnaz
authors.forename: Edward W
authors.initials: EW
authors.lastname: Davis
authors.forename: Harald
authors.initials: H
authors.lastname: Gross
authors.forename: Philippe
authors.initials: P
authors.lastname: Lemanceau
authors.forename: Joyce E
authors.initials: JE
authors.lastname: Loper
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001681:Biological Assay; D019295:Computational Biology; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D007501:Iron; D013058:Mass Spectrometry; D008958:Models, Molecular; D016296:Mutagenesis; D009842:Oligopeptides / Q000378:metabolism*; D010802:Phylogeny; D011487:Protein Conformation; D011549:Pseudomonas / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D001425:Bacterial Outer Membrane Proteins; D009842:Oligopeptides; C042453:pyoverdin; D007501:Iron