Two ABC transporter systems participate in siderophore transport in the marine pathogen Vibrio anguillarum 775 (pJM1).

ORF40 (named fatE) in the Vibrio anguillarum pJM1 plasmid-encoding anguibactin iron transport systems is a homolog of ATPase genes involved in ferric-siderophore transport. Mutation of fatE did not affect ferric-anguibactin transport, indicating that there must be other ATPase gene(s) in addition to fatE. By searching the genomic sequence of V. anguillarum 775(pJM1), we identified a homolog of fatE named fvtE on chromosome 2. It is of interest that in this locus, we also identified homologs of fatB, fatC, and fatD that we named fvtB, fvtC and fvtD, respectively. The fvtE mutant still showed ferric-anguibactin transport, while the double fatE and fvtE mutation completely abolished the ferric-anguibactin transport indicating that fatE and fvtE are functional ATPase homologs for ferric-anguibactin transport. Furthermore, we demonstrate that fvtB, fvtC, fvtD, and fvtE are essential for ferric-vanchrobactin and ferric-enterobactin transport.