IutB participates in the ferric-vulnibactin utilization system in Vibrio vulnificus M2799.
Vibrio vulnificus, an opportunistic pathogen that causes a serious, often fatal, infection in humans, requires iron for its growth. This bacterium utilizes iron from the environment via the vulnibactin-mediated iron uptake system. The mechanisms of vulnibactin biosynthesis, vulnibactin export, and ferric-vulnibactin uptake systems have been reported, whereas the ferric-vulnibactin reduction mechanism in the cell remains unclear. The results of our previous study showed that VuuB, a member of the flavin adenine dinucleotide-containing siderophore-interacting protein family, is a ferric-vulnibactin reductase, but there are other reductases that can complement for the defective vuuB. The aim of this study was to identify these proteins that can complement the loss of function of VuuB. We constructed mutants of genes encoding putative reductases in V. vulnificus M2799, and analyzed their growth under low-iron conditions. Complementation analyses confirmed that IutB, which functions as a ferric-aerobactin reductase, participates in ferric-vulnibactin reduction in the absence of VuuB. This is the first genetic evidence that ferric-vulnibactin is reduced by a member of the ferric-siderophore reductase protein family. In the aerobactin-utilization system, IutB plays a major role in ferric-aerobactin reduction in V. vulnificus M2799, and VuuB and DesB can compensate for the defect of IutB. Furthermore, the expression of iutB and desB was found to be regulated by iron and a ferric uptake regulator.
Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan.
Hiroaki
H
Kawano
Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan.
Katsushiro
K
Miyamoto
Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan.
Miho
M
Negoro
Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan.
Eriko
E
Zushi
Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan.
Takahiro
T
Tsuchiya
Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama, Ehime, 790-8578, Japan.
Tomotaka
T
Tanabe
Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama, Ehime, 790-8578, Japan.
Tatsuya
T
Funahashi
Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan. tsujibo@gly.oups.ac.jp.
Hiroshi
H
Tsujibo
D000577:Amides / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003676:Deferoxamine / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D005822:Genetic Vectors / Q000737:chemistry / Q000378:metabolism; D006877:Hydroxamic Acids / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D009154:Mutation; D010080:Oxazoles / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D017262:Siderophores / Q000737:chemistry / Q000378:metabolism*; D041261:Vibrio vulnificus / Q000235:genetics / Q000378:metabolism*
D000577:Amides; D001426:Bacterial Proteins; D006877:Hydroxamic Acids; D010080:Oxazoles; D011994:Recombinant Proteins; D017262:Siderophores; C086667:vulnibactin; C031819:aerobactin; D007501:Iron; D010088:Oxidoreductases; D003676:Deferoxamine
Aerobactin; Clinical isolate; Desferrioxamine B; Ferric-siderophore reductase; Siderophore; Siderophore-interacting protein