title: High cellular organization of pyoverdine biosynthesis in Pseudomonas aeruginosa: clustering of PvdA at the old cell pole.
abstract: Pyoverdine I (PVDI) is the major siderophore produced by Pseudomonas aeruginosa PAO1 to import iron. Its biosynthesis requires the coordinated action of cytoplasmic, periplasmic and membrane proteins. The individual enzymatic activities of these proteins are well known. However, their subcellular distribution in particular areas of the cytoplasm, periplasm, or within the membrane has never been investigated. We used chromosomal replacement to generate P.aeruginosa strains producing fluorescent fusions with PvdA, one of the initial enzymes in the biosynthetic pathway of PVDI in the cytoplasm, and PvdQ, involved in the maturation of PVDI in the periplasm. Cellular fractionation indicated that a substantial amount of PvdA-YFP was located in the membrane fraction. Epifluorescence microscopy imaging showed that PvdA-YFP was mainly clustered at the old cell pole of bacteria, indicating a polar segregation of the protein. Epifluorescence and TIRF imaging on cells expressing labelled PvdQ showed that this enzyme was uniformly distributed in the periplasm, in contrast with PvdA-YFP. The description of the intracellular distribution of these enzymes contributes to the understanding of the PVDI biosynthetic pathway.
authors.affiliation: UMR 7242, Université de Strasbourg-CNRS, ESBS, Blvd Sébastien Brant, F-67413 Illkirch, Strasbourg, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Guillon
authors.forename: Maher
authors.initials: M
authors.lastname: El Mecherki
authors.forename: Stephan
authors.initials: S
authors.lastname: Altenburger
authors.forename: Peter L
authors.initials: PL
authors.lastname: Graumann
authors.forename: Isabelle J
authors.initials: IJ
authors.lastname: Schalk
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D009842:Oligopeptides / Q000096:biosynthesis* / Q000235:genetics; D019897:Periplasm / Q000378:metabolism; D055550:Protein Stability; D011550:Pseudomonas aeruginosa / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D017262:Siderophores / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D009842:Oligopeptides; D017262:Siderophores; C042453:pyoverdin; D007501:Iron; D006899:Mixed Function Oxygenases; C524418:ornithine hydroxylase, Pseudomonas aeruginosa