Wyckoff, E.E., A. M. Valle, S. L. Smith, and S. M. Payne. 1999. A multifunctional ATP-binding cassette transporter system from Vibrio cholerae transports vibriobactin and enterobactin. Journal of Bacteriology. 181(24):7588-96
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.
