title: Identification and characterization of an iron ABC transporter operon in Gluconacetobacter diazotrophicus Pal 5.
abstract: Gluconacetobacter diazotrophicus is a nitrogen-fixing bacterium and endophyte of sugarcane. We have cloned and sequenced the genes coding for the components of the iron ABC-type acquisition system of G. diazotrophicus. Sequence analysis revealed three ORFs, (feuA, feuB, and feuC) organized as an operon and encoding polypeptides of 346 (38 kDa), 342 (34.2 kDa), and 240 (26 kDa) amino acids, respectively. The deduced translation products of the feu operon showed similarity with a periplasmic solute-binding protein (FeuA), permease (FeuB), and ATPase (FeuC) involved in Fe transport. The role of FeuB in the survival of G. diazotrophicus under iron depletion was evaluated by comparing the ability of wild-type and FeuB-Km(R) -mutant strains in a medium without iron supplementation and in a medium containing 2, 2'-dipyridyl (DP). Growth of the mutant was affected in the medium containing DP. The operon was expressed at higher levels in cells depleted for iron than in those that contained the metal. A decrease in nitrogenase activity was observed with the FeuB-Km(R) -mutant strain that with the wild-type under iron deficiency conditions, suggesting that the Feu operon play role in Fe nutrition of G. diazotrophicus.
authors.affiliation: Instituto de Ciencias, Centro de Investigaciones Microbiológicas, Benemérita Universidad Autónoma de Puebla, Apdo. Postal 1622, Puebla, Puebla, Mexico.
authors.forename: Lucia Soto
authors.initials: LS
authors.lastname: Urzúa
authors.forename: Ada P
authors.initials: AP
authors.lastname: Vázquez-Candanedo
authors.forename: Adriana
authors.initials: A
authors.lastname: Sánchez-Espíndola
authors.forename: Carlos Ávila
authors.initials: CÁ
authors.lastname: Ramírez
authors.forename: Beatriz E
authors.initials: BE
authors.lastname: Baca
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000251:Adenosine Triphosphatases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D001692:Biological Transport; D041821:Gluconacetobacter / Q000235:genetics* / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics; D009586:Nitrogen Fixation; D009876:Operon; D033902:Periplasmic Binding Proteins / Q000235:genetics; D031786:Saccharum / Q000382:microbiology
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D033902:Periplasmic Binding Proteins; D007501:Iron; D000251:Adenosine Triphosphatases