Metal trafficking via siderophores in Gram-negative bacteria: specificities and characteristics of the pyoverdine pathway.
Under iron-limiting conditions, fluorescent pseudomonads secrete fluorescent siderophores called pyoverdines (Pvd), which form complexes with iron that are then taken up by the bacteria. Pvds consist of a fluorescent chromophore derived from 2,3-diamino-6,7-dihydroxyquinoline and containing one of the bidentate groups involved in iron chelation, linked to a peptide moiety containing the other two bidentate groups required for binding to Fe3+. More than 100 different Pvds have been identified, with different peptide sequences, forming a wide family of siderophores. In the human opportunistic pathogen Pseudomonas aeruginosa, Pvd is necessary for infection and is considered to be a virulence factor. This review focuses on the mechanisms underlying iron uptake by the Pvd pathway in pseudomonads, taking into account recent biochemical and biophysical studies and recently solved 3D-structures of the Pvd outer membrane transporter FpvA in four different loading states. These data are discussed and compared with the mechanisms of siderophore-Fe uptake reported for other Gram-negative bacteria.
Schalk
Isabelle J
IJ
Université Strasbourg 1, Institut Gilbert Laustriat, CNRS - UMR 7175, ESBS, 67412 Illkirch Cedex, France. schalk@esbs.u-strasbg.fr
D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D008670:Metals / Q000378:metabolism*; D008958:Models, Molecular; D009842:Oligopeptides / Q000378:metabolism*; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D017262:Siderophores / Q000378:metabolism*
D001425:Bacterial Outer Membrane Proteins; D008670:Metals; D009842:Oligopeptides; D017262:Siderophores; C042453:pyoverdin; D007501:Iron