title: Role of periplasmic binding proteins, FatB and VatD, in the vulnibactin utilization system of Vibrio vulnificus M2799.
abstract: Vibrio vulnificus, an opportunistic marine bacterium that causes a serious, often fatal, infection in humans, requires iron for its pathogenesis. This bacterium uses iron from the environment via the vulnibactin-mediated-iron-uptake system. In this study, we constructed the deletion mutants of the genes encoding the proteins involved in the vulnibactin-mediated-iron-uptake system, isochorismate synthase (ICS), vulnibactin utilization protein (VuuB), periplasmic ferric-vulnibactin binding protein (FatB), and ferric-vulnibactin receptor protein (VuuA). The Δics and ΔvuuA mutants were unable to grow under low-iron concentration conditions compared with the isogenic wild-type, indicating that the involvement of ICS in the vulnibactin biosynthesis pathway and uptake of ferric-vulnibactin through the VuuA receptor protein are essential for V. vulnificus M2799 growth under low-iron concentration conditions. Similar growth impairment was also observed in ΔfatB, with growth recovery of this mutant observed 6 h after the beginning of the culture. These results indicate that there must be other periplasmic ferric-vulnibactin binding proteins in V. vulnificus M2799 that complement the defective fatB gene. Complementary growth studies confirmed that VatD protein, which functions as a periplasmic ferric-aerobactin binding protein, was found to participate in the ferric-vulnibactin uptake system in the absence of FatB. Furthermore, the expression of ics, vuuB, fatB, vuuA, and vatD genes was found to be regulated by iron and the ferric uptake regulator.
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kawano
authors.forename: Katsushiro
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Itsumi
authors.initials: I
authors.lastname: Sakaguchi
authors.forename: Tomoka
authors.initials: T
authors.lastname: Myojin
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Moriwaki
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tsuchiya
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Tanabe
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsujibo
mesh_terms: D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000577:Amides / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D006877:Hydroxamic Acids / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010080:Oxazoles / Q000378:metabolism*; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D017384:Sequence Deletion / Q000235:genetics; D017262:Siderophores / Q000378:metabolism; D014735:Vibrio Infections / Q000188:drug therapy / Q000235:genetics; D041261:Vibrio vulnificus / Q000235:genetics / Q000378:metabolism*
chemical_list: D000577:Amides; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D006877:Hydroxamic Acids; D026901:Membrane Transport Proteins; D010080:Oxazoles; D033903:Periplasmic Proteins; D017262:Siderophores; C086667:vulnibactin; C031819:aerobactin; D007501:Iron; D000123:Acetyltransferases; C477287:virginiamycin acetyltransferase D
keywords: ABC-type transporter; Iron acquisition; Vibrio vulnificus; Vulnibactin