title: The crystal structure of the pyoverdine outer membrane receptor FpvA from Pseudomonas aeruginosa at 3.6 angstroms resolution.
abstract: The pyoverdine outer membrane receptor FpvA from Pseudomonas aeruginosa translocates ferric-pyoverdine across the outer membrane via an energy consuming mechanism that involves the inner membrane energy transducing complex of TonB-ExbB-ExbD and the proton motive force. We solved the crystal structure of FpvA loaded with iron-free pyoverdine at 3.6 angstroms resolution. The pyoverdine receptor is folded in two domains: a transmembrane 22-stranded beta-barrel domain occluded by an N-terminal domain containing a mixed four-stranded beta-sheet (the plug). The beta-strands of the barrel are connected by long extracellular loops and short periplasmic turns. The iron-free pyoverdine is bound at the surface of the receptor in a pocket lined with aromatic residues while the extracellular loops do not completely cover the pyoverdine binding site. The TonB box, which is involved in intermolecular contacts with the TonB protein of the inner membrane, is observed in an extended conformation. Comparison of this first reported structure of an iron-siderophore transporter from a bacterium other than Escherichia coli with the known structures of the E.coli TonB-dependent transporters reveals a high structural homology and suggests that a common sensing mechanism exists for the iron-loading status in all bacterial iron siderophore transporters.
authors.affiliation: Département Récepteurs et Protéines Membranaires, UPR9050 CNRS, Ecole Supérieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67412 Illkirch, France. cobessi@esbs.u-strasbg.fr
authors.forename: David
authors.initials: D
authors.lastname: Cobessi
authors.forename: Herve
authors.initials: H
authors.lastname: Celia
authors.forename: Nicolas
authors.initials: N
authors.lastname: Folschweiller
authors.forename: Isabelle J
authors.initials: IJ
authors.lastname: Schalk
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Abdallah
authors.forename: Franc
authors.initials: F
authors.lastname: Pattus
mesh_terms: D000494:Allosteric Regulation; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017262:Siderophores / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; C082326:FpvA protein, Pseudomonas aeruginosa; D009842:Oligopeptides; D017262:Siderophores; C042453:pyoverdin