A multifunctional ATP-binding cassette transporter system from Vibrio cholerae transports vibriobactin and enterobactin.
Vibrio cholerae uses the catechol siderophore vibriobactin for iron transport under iron-limiting conditions. We have identified genes for vibriobactin transport and mapped them within the vibriobactin biosynthetic gene cluster. Within this genetic region we have identified four genes, viuP, viuD, viuG and viuC, whose protein products have homology to the periplasmic binding protein, the two integral cytoplasmic membrane proteins, and the ATPase component, respectively, of other iron transport systems. The amino-terminal region of ViuP has homology to a lipoprotein signal sequence, and ViuP could be labeled with [(3)H]palmitic acid. This suggests that ViuP is a membrane lipoprotein. The ViuPDGC system transports both vibriobactin and enterobactin in Escherichia coli. In the same assay, the E. coli enterobactin transport system, FepBDGC, allowed the utilization of enterobactin but not vibriobactin. Although the entire viuPDGC system could complement mutations in fepB, fepD, fepG, or fepC, only viuC was able to independently complement the corresponding fep mutation. This indicates that these proteins usually function as a complex. V. cholerae strains carrying a mutation in viuP or in viuG were constructed by marker exchange. These mutations reduced, but did not completely eliminate, vibriobactin utilization. This suggests that V. cholerae contains genes in addition to viuPDGC that function in the transport of catechol siderophores.
Wyckoff
E E
EE
Department of Molecular Genetics and Microbiology, and Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712-1095, USA. ewyckoff@mail.utexas.edu
Valle
A M
AM
Smith
S L
SL
Payne
S M
SM
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / 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; D001693:Biological Transport, Active; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002396:Catechols / Q000378:metabolism*; D004758:Enterobactin / Q000378:metabolism*; D008969:Molecular Sequence Data; D010080:Oxazoles; D011956:Receptors, Cell Surface; D017262:Siderophores / Q000378:metabolism; D014734:Vibrio cholerae / Q000235:genetics / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002396:Catechols; D010080:Oxazoles; D011956:Receptors, Cell Surface; D017262:Siderophores; C089365:ViuB protein, Vibrio cholerae; C075171:ViuA protein, Vibrio cholerae; D004758:Enterobactin; C040227:vibriobactin; D002265:Carboxylic Ester Hydrolases; D000251:Adenosine Triphosphatases