title: Characterization of a gene encoding the outer membrane receptor for ferric enterobactin in Aeromonas hydrophila ATCC 7966(T).
abstract: Aeromonas hydrophila ATCC 7966(T) produces a catecholate siderophore amonabactin in response to iron starvation. In this study, we determined that this strain utilizes exogenously supplied enterobactin (Ent) for growth under iron-limiting conditions. A homology search of the A. hydrophila ATCC 7966(T) genomic sequence revealed the existence of a candidate gene encoding a protein homologous to Vibrio parahaemolyticus IrgA that functions as the outer membrane receptor for ferric Ent. SDS-PAGE showed induction of IrgA under iron-limiting conditions. The growth of the double mutant of irgA and entA (one of the amonabactin biosynthetic genes) was restored when it was complemented with irgA in the presence of Ent. Moreover, a growth assay of three isogenic tonB mutants indicated that the tonB2 system exclusively provides energy for IrgA to transport ferric Ent. Finally, reverse transcriptase-quantitative PCR revealed that the transcription of irgA and the TonB2 system cluster genes is iron-regulated, consistently with the presence of a predicted Fur box in the promoter region.
authors: College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Japan. tfunahas@cc.matsuyama-u.ac.jp
authors: Tatsuya
authors: T
authors: Funahashi
authors: Tomotaka
authors: T
authors: Tanabe
authors: Katsushiro
authors: K
authors: Miyamoto
authors: Hiroshi
authors: H
authors: Tsujibo
authors: Jun
authors: J
authors: Maki
authors: Shigeo
authors: S
authors: Yamamoto
mesh_terms: D016980:Aeromonas hydrophila / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001692:Biological Transport; D004758:Enterobactin / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D007501:Iron / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014734:Vibrio cholerae / Q000235:genetics / Q000378:metabolism; D014736:Vibrio parahaemolyticus / Q000235:genetics / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; C074789:irgA protein, Vibrio cholerae; C057616:tonB protein, Bacteria; D004758:Enterobactin; D007501:Iron; D044925:Oxidoreductases Acting on CH-CH Group Donors